My engine is an oily mess (a work in progress)
 

Hello everyone,

When I bought my D24T-powered 740 back in 2007 it had a noticeable oil leak. I figured "hey, it's an old car, and I'll just fix it, no problem". I actually posted this type of message on the "volvo_diesels" mailing list around the same time. Fast forward to now and the leak is much worse. It will leak about a quart of oil in 750 or so miles. The jet black markings of my car are well represented in both my work's parking lot, and my home turf.

I cannot determine the exact source of the leak. It is built up on the oil pan, turbo, turbo intake tract, oil cooler, near the front of the engine at the crank, etc. My plan is to degrease and entire area, hose it down, and see if I can figure out where the oil is coming from. If I cannot, I'll clean it again and add some oil dye, and repeat.

My front suspension is in dire need of a rebuild but I'd rather not begin this job until that area is not a greasy, sticky, horrid mess! I'll update this thread with pictures and information as I tackle the clean up and investigation.

It begins tomorrow! :eek:

Update #1:

I de-greased the front bottom half of the engine as this was the worst or it. A significant collection of oily grime was on the bottom half of the alternator, front of the sump, oil filter, and where the oil pump and engine block meet. The oil cooler and its two coolant lines were free of oil. Looking at my VADIS diagrams I see there is an oil pump gasket (p/n 3507028) and naturally the oil pan gasket as plausible culprits.

There is a thick and sticky coating of oil on the front of the cross member. I suppose this is due to the oil leaking at speed and splashing on the cross member as it travels rearward.

I have a few questions based on my limited research and what I've been able to see on the car:

1. Are the seals used on the timing belt cover only used to keep debris out of the belt?
2. Are there any additional paths where oil can escape on the front of the engine? I'm ruling the head gasket out as the engine is dry at that level.
3. Is there a front crankshaft seal? My VADIS does not show one, and Rock Auto seems vague.

Here is a pic of after the initial clean up:

https://picasaweb.google.com/lh/phot...eat=directlink

There is a front crankshaft seal that the pulley rides on which could be leaking, also the oil pump gasket at the block could be leaking as well. I have seen the oil cooler o-rings petrified on a few different vw diesels, so they are suspect, as is the seal at the block where the oil filter/cooler adapter assembly bolts on. The rubber seal on the cover is pretty much a dust cover, or to keep it from being metal on metal and rattling and making noise I suspect. Your picture also shows the compressor housing of the turbo being oily, which can be from crank case blow by oil draining into the intake tract and leaking out where the intake neck attaches to the turbo, though I doubt your loosing much oil there. It sounds like you should be able to start it up and see a rather aparent leak at the amount of oil your loosing.

Jason

Glad to hear you are going to tackle it! You and the car will both be glad you did. :-)

As you have already found, diagnosing oil leaks in this area can be tricky since the mess goes everywhere as soon as the car gets driven. As Jason suggested, start with the easy and obvious... don't assume it is a front crank seal or oil pump gasket leak unless you can see the leakage obviously coming from there. Oil cooler seals can leak, the turbo inlet can drip large amounts of oil from the CCV system or have leaks from the oil supply/return lines, a common valve cover gasket leak can come all the way down and simulate leakage from a different area.... etc.

One suggestion: due to the exposure of this area of the engine to wind from the radiator fan and/or airflow around the car at speed, rather than cleaning the area and then driving the car to see where the leak is coming from, you may have better results from cleaning it and then running the engine with the car stationary as far as pinpointing the leak source. If you have a weekend day free, you can idle the motor for several hours or all day if necessary. (If your car is an automatic, though, be sure to do this with the transmission in 1st gear and the rear wheels off the ground on jack stands -- idling for very long periods in neutral can cook an otherwise healthy ZF trans, and idling in gear for very prolonged periods can lead to overheating of the trans fluid.)

Hope you are able to figure it out! One other thing to look at -- take the upper timing belt cover loose and look inside for evidence of oil leakage. If the leak is coming from the front main seal, you will also see oil everywhere inside the belt cover -- the TB acts like a conveyor belt and flings the oil all over the place. If it is dry in there (and you hope it is), then the crank and cam seals are fine. If it is not dry, then you have found your issue, and you do not want to even crank the engine again until you have fixed it... oil contamination weakens timing belts, and if that belt breaks, your engine is hosed!

Thank you for the responses to my oil-related ailments. I apologize for the prolonged radio silence but life gets in the way of our hobbies sometimes. The Volvo has been sitting so long the battery has lost its charge. I'm going to de-grease once more and check behind the front timing belt cover for oil. If this area is dry I'll charge the battery, start the engine, and play the waiting game. It is an auto so I will take your advice v8volvo and put the rear on jack stands.

Ideally I'd like to get this sorted before winter rolls in. I've lost a good amount of time but if I'm lucky I should be able to make some progress.

And we're off!
 

If you're also a reader of the D24 Mailing List you might recall the tale of a D24T owner who's oil cooler went bad and introduced oil into the coolant, and coolant into the oil. This prompted a multi-day conversation on the proper non-sudsing soap to use. I am that owner, and now I'm able to start to remedy the situation.

Today I drained the oil and coolant. The coolant was about 75% green coolant and 25% oil. I couldn't find a petcock valve on the radiator so I removed the lower radiator hose. Per the advice of E C Yarter on the D24 ML I purchased an "oil filter adapter" from eBay to replace the oil cooler. This adapter has 3 threaded 1/8 NPT bungs to screw in plugs, temperature senders, pressure senders, etc. I have a VDO oil temperature sender in one and the other two holes are taped and plugs inserted. The adapter comes with a 3/4-16 male-to-female threaded fitting. I also purchased an OEM D24 double-male oil filter nipple (PN 1257040). Assembly goes as follows:

Oil mount -> double male nipple -> oil filter adapter -> 3/4-16 threaded fitting -> oil filter.

I think it'll work out pretty well and I can monitor the temps now that the cooler is gone. Tomorrow I'll install the adapter and associated items, and a new filter. Once we're buttoned up I'll fill with new oil in the engine and 1 cap full of washing powder and water into the overflow reservoir. According to some folks on the ML this could take 8-10 times of filling, rinsing, draining; ugh.

I do have a question: is the lower radiator hose available in the US? I see on RockAuto they list "ÜRO PARTS Part # 1257992" for $12.76 ... but those European-sourced parts can be awful pricey to ship. :eek:

I'm also going to head to the home store and source some brass plumbing plugs. These are for the coolant hoses I won't be needing with the removal of the oil cooler. Yippie!

Good luck with your cleaning process! After the cleaning is a good time for all new hoses and a new radiator, especially if you were planning to do it anyway. I'm not sure about hose availability.

Do you have a link to that oil adapter? I really like that idea as a way to add an oil temp gauge to a D24. If you saw my thread on the giant oil cooler I added, I'm now slightly concerned that I'll be over-cooling my oil as the thermostat I used doesn't fully block off flow to the external cooler.

Hi Tyler,

Yes I was planning on buying one of those Nissens radiators off eBay as discussed in this forum. I'll need to investigate the hosts in general and check their availability. Perhaps a separate thread is best for this. I'm sure all of the hoses are in need of replacement anyway.

Here is a link to the exact same product and seller I bought mine from:

http://www.ebay.com/itm/Brand-New-Si...-/400543800040

I needed to debur a few of the internal surfaces of that adapter with a small file. Otherwise it performs as advertised. As mentioned before I opted to buy the D24 double-male oil filter nipple as opposed to cutting the D24T threaded nipple used with the oil cooler. Using the D24 nipple with the adapter's threaded male-female adapter gives a very secure fitting without the need of the OE nipple's nut or using something like Locktite. I'm not sure if I'm describing that well enough. :D

More removal ...
 

I finally removed the oil cooler and the threaded "oil pipe" from the engine. I'm glad to have these items gone. I still need to fully remove the two coolant hoses formerly connected to the oil cooler. A trip to the home store for a few brass plumbing plugs seems to be the agreed on method on plugging up the now exposed coolant circuit.

I did note that the large o-ring from behind the oil cooler looked a bit brittle. It was still rubbery, but it did look to be old and perhaps capable of leaking oil at a high-rate of PSI; interesting. :confused:

I have the OEM double-male nipple, the adapter's male-female threaded nipple, and finally the oil adapter installed. The adapter is so shiny and the VDO temperature sender is too very shiny. Those pieces really illustrate the horrific oily mess that the front passenger-side quadrant of the engine really is. I'll update this thread with some pictures soon.

Update: with the oil adapter's threaded nipple screwed fully into the engine the oil adapter itself it loose enough to turn with your hand. So it seems as though I need some type of a shim to push the adapter further down on the engine so tightening the adapter fitting seals the adapter to the engine. This ought to be interesting.

A big thanks to Anders for his help in providing a part number to a much needed freeze plug!

The last few days have been very productive for the Volvo. I have removed the oil cooler and its associated plumbing. I decided to skip the installation of the oil adapter as the car was parked on a public street and the neighborhood "passive-aggressives" were in force. Instead I installed the new OEM double-male oil filter nipple with blue Loctite on its threads and a new Wix oil filter (sans Loctite!).

The oil cooler hose that plugs into the block at the thermostat housing was a real bear to tackle. I tried tapping the hose barb out of the block with a punch, but as the engine is installed in the car this proved very tedious. Instead I took the low road of cutting the barb with a cut-off wheel and sawing and punching until the barb could take no more. I even managed to spare the block any damage, hizzah! I installed a Dorman (PN 555-016) freeze plug at 23.90mm width with red Loctite.

At this point I still need to address the coolant barb at the rear of the cylinder head. A freeze plug would be ideal but it's too cramped back there. Instead I'll use a hose plug and (hopefully) call it good. At this point the engine is ready to receive its fluids and multiple applications of the cooling system flush regime.

Question: I removed the thermostat as it was (probably) in need of replacement. I planned on keeping it out for the duration of the flushing. My logic was no thermostat would provide better soapy water flow; thoughts?

Makes sense to me to run with the thermostat for most effective flushing of the rad, but you're going to replace the rad anyway, right? Either way shouldn't hurt, might not want to run it that way too long but in summer weather probably OK for a little while.

Good to know there is a freeze plug that can fit in that hole -- I had wondered the same thing. Much nicer solution than a rubber plug!

On hoses -- the lower hose is still pretty readily available. IMC sells good-quality Mackay hoses, both upper and lower, so any IMC reseller should be able to get those for you. Here is one such reseller that offers great prices -- usually within a few cents of IMC wholesale shop cost when I have looked:

Upper hose part # is 1257347 https://www.gowestyautoparts.com/OEM...search=1257347
Lower hose part # 1257992 https://www.gowestyautoparts.com/OEM...search=1257992

Unfortunately the rad hoses are the only ones available aftermarket for D24 and D24T, as far as I have seen. The smaller dia. hose from the expansion tank to the cold tank of the rad is the same as used on gasser and is also available, but heater hoses are from Volvo only. Not difficult to fabricate from scratch, though. Here was one setup that worked well: http://www.d24t.com/showthread.php?t=608

For blocking off the oil cooler hose connection on the back of the head, theoretically would be possible to do the same thing as you did in the block if you could get enough access. D24 engines, which don't have the oil cooler and attendant hoses, have a small freeze plug installed where the (removable) hose connection is mounted on a D24T. You could remove the hose barb and have someone fill it up with weld, or try to get a freeze plug in, or use a rubber hose block-off cap -- but those caps never seem to last very long, being designed I think as a cheap temporary solution for desperate people with leaking heater cores... :rolleyes: All the ones I have seen installed in that location have cracked and burst within a few months, don't know if it's from the high heat exposure or just junk material. Maybe you can find a good-quality one meant for permanent installation, but if you can avoid using one at all, that seems like it might be the best setup. Will be interested to hear what you are able to figure out...

some have a blanking plate held in by a screw off to the side.

I don't like running without the thermostat, as part of the 'open stat' position is to close the 'cold stat' recirc hole....so you end up recirculating extra, with a cool radiator. I pin a thermostat open, then install it.

Man, George, that is some great news. I anticipated that those hoses would cost a small gold mine!

I think once the flushing processes are completed I'm going to follow your advice and make the other hoses. Cheap to create and easier to replace when the time comes.

The rear cylinder head coolant bung is something I'd like a permanent fix to. Admittedly I've never poked around back there so that's my first step.

Yes please!
 

Oh man, this is the solution I've been looking for! :D What cars had this blanking plate? I assume D24 engines, did some have freeze plugs and others blanking plates?

Based on George's thoughts and yours I'll put the thermostat back in. Oh and yes, I am going to replace that radiator, it was getting pretty long in the tooth before the oil cooler failure.

O-rings ...
 

In the mean time I'm going to re-use the right angle coolant plug for the rear of the cylinder head. The o-ring was very hard and split in two pieces on removal. Being proactive I went to the local Grainger which surprisingly had nothing that was close enough. Tyler on the D24 ML mentioned an A/C repair kit from Harbor Freight having the right o-ring. Looking at their website I see a "397 Piece Metric O-Ring Assortment" or a "225 Piece Metric Nitrile O-Ring Assortment" each under $10. I think I'll go this route and report back.

I mean really, you can never have enough o-rings! :D

She's a runner!
 

A little update ...

I started the car today about an hour ago after approximately 2 weeks of working on it. Fired right up! Here's what I accomplished since I last posted:

1. Removed and reinstalled the intake manifold to removed the long coolant pipe which travels to the read of the cylinder head.
2. Cleaned the rear coolant flange, installed a new o-ring, and fitted a small section of hose and a plug to temporarily seal the rear coolant passage.
3. Reinstalled the Wahler thermostat.
4. Added oil, soap, and water, checked for leaks and ran the engine for about 10 minutes.

For the o-ring I purchased the Harbor Freight "225 PC. Nitrile O-ring Assortment"; item 67609. This kit comes with a lot of o-rings, from a 3mm ID to a 22mm ID. For the rear coolant flange I used a "G22 22x3mm" o-ring. This fits appropriately snug around the flange neck and is thick enough to mimic that of the o-ring that was installed.

Kit was $4.99 on sale for $3.99 minus a 20% off coupon for $3.19. Naturally I also used my free flashlight coupon, too. :p

I plan to drive the car locally to get the temperature up and the soap flowing. I'll drain as time provides, but I believe it'll take 8-10 times. Then I'll replace the hoses, radiator, and a good coolant/distilled water mix; and call it winter.

I took the car for a quick spin (under 1.5 miles) and once I got down the road the temperature gauge started moving very high. Right before cutting the engine the needle suddenly jerked to the left, then straight up, and again to the right. My dashboard was otherwise behaving appropriately. Now I know my cooling capacity is reduced by having water and soap in the system, and a radiator with oil in it, but it still surprised me.

Could an air bubble cause this erratic gauge behavior?

In other news I think I have found the source of the oil leak! It's my headgasket that is leaking, oh joy. :D The gasket is a 3-notch fiber which I can only assume is in desperate need of replacing -- aside from the external leak. I'm wondering, could I just tighten up the head bolts in the mean time to try and squeeze the leak shut?

The draining and filling regime starts today and I hope to have it completed in two weeks or so. New radiators are in transit, too. Thanks for any advice.

Detergent should not cause erratic temp gauge behavior. Wouldn't expect to see an air bubble in the temp sensor area EXCEPT maybe in a low coolant situation. Specifically, similar behavior (temp gauge rises sharply, then falls to below normal) can indicate a major leak since coolant loss will leave the temp sensor high and dry. The sensor cannot register the temp of steam very well.

How long has it been since the last time you drove the car on a longer trip, long enough to have reached operating temp for say, 10 minutes? Was the coolant level normal? Have you refilled since then?

1.5 miles not really far enough to reach operating temp? When you opened the hood did the engine feel or smell overheated?

It could be elec. connection or flakey gauge but verify for sure. One cannot be too careful regarding overheating these engines.

Where is the oil leaking from? Both of mine leak just under the vacuum pump area. It is NOT the vacuum pump leaking.

Thanks for the reply. I have not driven the car on any real distance as the gauge freaks me out and I opt to keep things very local. I drained the oily water-soap today from the radiator. It wasn't much liquid. I suppose the thermostat didn't open. Here is what I was assuming I would do to get things cleaned out:

1. Drain.
2. Fill with two cups of detergent and the rest water.
3. Start the engine with the coolant cap off.
4. Let it idle until the water level in the overflow tank drops. I assumed this to mean the thermostat opened and is pulling water/detergent into the block.
5. Top-off the overflow tank and allow the engine to continue idling. Monitor for engine temperature.
6. Repeat.

Is my process flawed? Silly question, but if I keep my expansion tank cap off will the thermostat ever open? Does the thermostat need both temperature and pressure to function properly? I've never thought to think about this until now.

Oil is coming from the passenger-side (US-spec) between the cylinder head and the block. Near the front of the engine underneath the exhaust manifold.

I have had two D24t's valve covers leak at the front bearing cap. It leaked down the front of the cylinder head and followed the head gasket, making it look like the head gasket was leaking, more so on the 240 then the 740 as the engine is slanted more to the passenger side.

See my comments in bold italics:

Oh yes, of course. I should have read my Green book! I never detached that hose so there must be a large air bubble in the system. That would explain a) the gauge reaction, and b) the small amount of fluid I drained / added. I bet once I loosen that hose the expansion tank level will drop as air is bled and more fluid is pulled in. Thanks ngoma!

Second drain and re-fill completed
 

When drained some additional oil poured out. This time I removed the injection pump thermostat hose to allow the system to burp. Filled the system and ran the engine. Eventually the idle speed began to slow as the wax thermostat began to move, at least it was getting the water/soap! The level in the expansion tank dropped about two inches and I added water at that point and shut her down. Tomorrow I'll drive the car a bit and nervously observe the temperature gauge.

On the flip side I've got this drain/re-fill process pretty streamlined. :D

I drove the car around the neighborhood for about 10 minutes or so. The temperature gauge acted normally, no erratic behavior or other gremlins to speak to. In my previous post I mentioned that the water level in the expansion tank dropped about ~1.5 inches and I took that to mean the thermostat had opened and pulled water in. After driving the car around I popped the hood and checked the hoses. The upper hose from the radiator to the cylinder head was very warm, even hot to the touch. Whereas the bottom hose from the thermostat to the lower radiator opening was slightly warm. Finally the hose leading to the injection pump wax thermostat housing was also warm.

Why wouldn't the lower radiator hose be hot like the upper? What way does coolant flow in the engine? Does coolant flow from the engine to the top of the radiator (hot), is cooled by the radiator, and exits from the lower radiator opening and through the thermostat? My goal here is to make sure the thermostat is opening, it must be as I didn't see any signs of overheating.

As a side note both my Nissen radiators I bought from eBay arrived yesterday, they're very nice quality and the price cannot be beat! :cool:

All engines pull from the lower hose so they have some cooling till the last drop of coolant is gone. You may have to block the rad with cardboard or something if you want to heat the whole system without running full load for awhile.

Thanks for the reply 'Greasel. I figured it was logical that the radiator had a temperature drop between its top and bottom. It's also logical to assume coolant is pulled from the bottom and filled from the top; why fight gravity if you don't have to?

I've also noted that the radiator fan is always spinning. As thought the fan clutch isn't "clutching" as one would expect.

The fan always spins whenever the engine is turning, even when the clutch is "disengaged" -- however it will spin much faster when the clutch engages. I have seen one or two where the visco clutch locked up and the fan spun at full speed all the time, but assuming yours is doing what it should, you'll hear it making lots of whooshing noises during the first minute or two after cold startup, then it will quiet down until air from rad gets hot enough to kick it on.

Glad to hear temp is staying where it should now -- definitely sounds like you had an air bubble in there before. We should make it a sticky on here or something about bleeding procedure so that members can be warned about this -- easy to cook the motor quickly if not all the air is gotten out. Good thing you caught it quickly! Paying attention to idle speed is a good way to watch out for it... every now and then even after I think I have gotten all the air out, I'll leave the motor running for a couple minutes and will hear the engine speed start rising again... Sometimes if you've got a persistent little chunk of air somewhere, putting the trans into low gear and driving around with the engine at higher RPM helps burp the last bit out -- seems like spinning the water pump faster helps.

I agree with Anders, the valve cover gasket can sometimes leak from hidden places and make the leak look like it's coming from somewhere else -- check again before concluding headgasket is at fault. If you have the multi-piece cork v/c gasket those really like to leak so makes it more likely. A leaky front cam seal might be able to simulate this as well. Anything leaking at the front will be blown towards the back by airflow thru the rad, but not the other direction, so often is a good method to find the highest and furthest-forward wet spot when trying to pinpoint the source of a leak. :)

Not quite gravity, think thermosyphoning.

In fact, early cars used thermosyphoning instead of water pumps.

Oh, right, of course. I've worked on a few slow-speed diesel generators like Lister, Lister-Petter, and some "Red Stone" models that are water cooled and use thermosyphoning for cooling. In those cases it's typically a 55-gallon barrel which contains the water. Thanks for the reply.

This is a very good tip to catching air pockets in the system. Is should be added to this proposed cooling system bleeding procedure!

If we build a coolant sticky, it may also be worth mention not all thermostats have the small bleed hole/notch that needs to be installed in the 12:00 position.

A coolant sticky is a good idea. The Whaler thermostat I have installed now does not have a bleed hole while I've got two spare Stant/Colorstat thermostats that do have the bleed hole.

An update on the "eBay" Nissen radiator I installed: it works perfect, it fit perfect, it was a great find.

Sometimes it is a notch in the sea that is hard to see.
I drill it out if it is missing.

T-stat shouldn't have an air bleed hole in this application. None of the "good" thermostats have the bleed hole, including any that you buy from the Volvo dealer's parts desk (or VW/Audi). It's not missing, rather it's not there by design, not needed due to the design of the system, having the t-stat in the lower rad hose rather than the upper hose means that the engine can be filled with coolant from the radiator (or expansion tank) through the open upper hose without creating an airlock. Only need that bleed hole if the t-stat is on top, so that air can escape from the high point while the engine is filled through the bottom hose. The way these motors are laid out, even with no bleed hole, the only part of the system that won't get filled as you pour coolant in (assuming you follow procedure for disconnecting a hose to vent air at the top of the motor) is the part of the lower rad hose that turns upward towards the motor, about a foot of hose from that turn to where it meets the t-stat housing. Drilling hole makes no difference, won't help though I guess doesn't hurt either. I suspect that the crappy Stant tstats just have it because they are also used in a jillion other applications, some of which may have the t-stat in a different position on the motor...

Strange then that the greenbook would be so specific about the hole being installed pointing up?

The only stat I ever bought from the dealer didn't open either way and was installed in my trash can.

"Installed in my trash can"
 

Just letting you know I will be borrowing and using this phrase in the future. It's perfect for those incorrect parts that can't be returned.

Interesting, I never looked at the book about this before, but I just did. As far as I could find, the book doesn't have anything about a t-stat bleed hole. It does instruct you to install the thermostat with the "arrow" pointed upwards. IIRC I have never bought or removed a t-stat for one of these that had an arrow on it (or a bleed hole). Without a bleed hole, hard to imagine why the orientation would matter much either. Perhaps they got rid of the arrow sometime during production when they figured out that it was pointless... wouldn't be the only running change made, the last run of water pumps Volvo dealers sold came without guide flanges on the side of the pulley so evidently there were revisions happening right up until the end. At any rate I don't mean to argue the point, but unless I'm looking in the wrong place I'm not seeing any mention of a hole. :confused:

I always just install them with the bridge running horizontal.

Third drain and re-fill completed
 

The nights are getting colder so I need to get a move on before things get too cold. Otherwise the car itself is behaving very well. Looking to put some miles on it this week and work on the 4th this weekend!

Fourth drain and re-fill completed
 

Trying for 2 a week!

Fifth drain and re-fill completed
 

It's still oily, but empirical evidence suggests that it's less oily. :D