Oily sludge and its eventual destruction (a work in progress)

[745 TurboGreasel]

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.

[Nevadan]

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.

[745 TurboGreasel]

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

[v8volvo]

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...

[745 TurboGreasel]

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.

[Nevadan]

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.

[v8volvo]

Originally Posted by 745 TurboGreasel

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

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.

I always just install them with the bridge running horizontal.

[jbg]

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!

[jbg]

Trying for 2 a week!

[jbg]

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