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Old 04-16-2018, 06:39 PM
VolvoGabe VolvoGabe is offline
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Default 1983 D24T running warm

Hi all, I have a 1983 760 Turbo Diesel that seems to be running warm at the moment.

I first bought it in January of this year and drove it 1100k's home. For a car that hadn't been started nor driven in 10 years it could not of ran better, apart from it liking to get warm - which was indicated via the temp gauge. The running hot when I first got it probably didn't good more than bad as it allowed the engine to blow out a lot of crap for sitting for 10 years, and god did it. From a gutless smoking freight train to a non smoking peppier sedan it loved the drive home.

I inspected some of the cooling system when I got home. The metal radiator was 3/4 blocked and that's all re-conditioned and installed back in the car. The car had no thermostat, and it still circulated as all the hoses and water in the expansion tank got warm. However, it now has a 90 degree thermostat and re-conditioned radiator but the reading on the temp gauge still climbs to what it was when I first drove it which is just over 3/4 high. The water doesn't seem to be circulating as when the temp gauge reads high, the bottom radiator hose and the expansion tank water are both vaguely warm/cold. Water pump condition is unknown, temp sensor condition is unknown.

What also confuses me is when I turn it off and leave it for a minute, and then start it back up the gauge reads just under half, and then when I start driving it around it goes back up.

Has anyone had any problems like this? Any help is appreciated. Thanks

Last edited by VolvoGabe; 04-16-2018 at 06:43 PM.
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  #2  
Old 04-17-2018, 01:27 PM
ngoma ngoma is offline
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Were you able to take temperature readings as suggested in this your post?

Make sure you installed the correct thermostat type. Should have the bypass blocking plate like this one:
Example photo.jpg

Otherwise too much coolant will just recycle thru the engine and never make it to/from the radiator. Same problem with running this engine with no thermostat. Overheat.

The bypass design is supposed to equalize engine temps (hot spots) and allow early heater before engine reaching operating temps.
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  #3  
Old 04-17-2018, 05:18 PM
VolvoGabe VolvoGabe is offline
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Originally Posted by ngoma View Post
Were you able to take temperature readings as suggested in this your post?

Make sure you installed the correct thermostat type. Should have the bypass blocking plate like this one:
Attachment 1154

Otherwise too much coolant will just recycle thru the engine and never make it to/from the radiator. Same problem with running this engine with no thermostat. Overheat.

The bypass design is supposed to equalize engine temps (hot spots) and allow early heater before engine reaching operating temps.
Hi, not yet however I did find that the 90 degree thermostat that was installed was faulty and was not opening. I removed that and took it for a drive and all hoses got hot and were same temp, which eliminates the water pump is a good sign, but the needle on the temp gauge stayed cold, on the C. Didn't even climb when the hoses were warm. Faulty temp sensor?
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Old 04-17-2018, 08:26 PM
v8volvo v8volvo is offline
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If the temp gauge stopped working at the same time that you replaced the tstat, possible there is an air pocket in the system. Good idea to make sure all air is bled out since this will also cause overheat if the pocket is large. Another possibility is that the wire got pulled off the gauge sender (at front of cylinder head just ahead of #1 glow plug) if the wiring harness that runs near the tstat housing got moved during the work.

90 degree tstat would be a little warmer than stock, 87C is the OE temp. 3C might be enough to make a visible difference on the gauge, these are quite sensitive. If the car had no thermostat installed when you got it, that's a clue that the warm running you are noticing was going on for a previous owner too. The plugged radiator could have been a cause, good that you found that and fixed it.

I would start by checking the electrical connections to the temp gauge sender and making sure the cooling system is well burped, then see what happens. First of all you need the gauge to work. If all the wiring appears OK, you can test the circuit and the gauge by grounding the connector for the sender. The gauge should read full hot with this wire grounded. If it does but you still get no reading when it is connected to the sender, then the sender is the issue (rare). If you get no reading when the wire is grounded, then the issue is with the gauge/cluster (rare) or a wiring connection somewhere between the engine and the dash (common). If you get to this point with no clear answers, reply back here and we can give some tips on further steps.

One factor with your 1983 model is that your temperature gauge shows variations in temperature around the operating set point. 700 series Volvos from late 1984 onward introduced "damped" dummy-style temperature gauges where the needle stays right in the middle for any temperature relatively close to operating temp, roughly 180F-210F. With those later gauges, the only time you see it move up is after a problem is already happening, so the early warning an accurate gauge provides is lost. On your gauge you will see minor fluctuations that are normal. An extra few degrees of operating temp might be visible with a hot thermostat, which the later style gauge would hide.

A few of us have had success running slightly cooler thermostats for improving temperature control in hot weather. If other checks don't turn up obvious problems this could be something to try.

As others suggested - if the car sat 10 years be sure to replace the timing belt.
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  #5  
Old 04-17-2018, 08:58 PM
VolvoGabe VolvoGabe is offline
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Quote:
Originally Posted by v8volvo View Post
If the temp gauge stopped working at the same time that you replaced the tstat, possible there is an air pocket in the system. Good idea to make sure all air is bled out since this will also cause overheat if the pocket is large. Another possibility is that the wire got pulled off the gauge sender (at front of cylinder head just ahead of #1 glow plug) if the wiring harness that runs near the tstat housing got moved during the work.

90 degree tstat would be a little warmer than stock, 87C is the OE temp. 3C might be enough to make a visible difference on the gauge, these are quite sensitive. If the car had no thermostat installed when you got it, that's a clue that the warm running you are noticing was going on for a previous owner too. The plugged radiator could have been a cause, good that you found that and fixed it.

I would start by checking the electrical connections to the temp gauge sender and making sure the cooling system is well burped, then see what happens. First of all you need the gauge to work. If all the wiring appears OK, you can test the circuit and the gauge by grounding the connector for the sender. The gauge should read full hot with this wire grounded. If it does but you still get no reading when it is connected to the sender, then the sender is the issue (rare). If you get no reading when the wire is grounded, then the issue is with the gauge/cluster (rare) or a wiring connection somewhere between the engine and the dash (common). If you get to this point with no clear answers, reply back here and we can give some tips on further steps.

One factor with your 1983 model is that your temperature gauge shows variations in temperature around the operating set point. 700 series Volvos from late 1984 onward introduced "damped" dummy-style temperature gauges where the needle stays right in the middle for any temperature relatively close to operating temp, roughly 180F-210F. With those later gauges, the only time you see it move up is after a problem is already happening, so the early warning an accurate gauge provides is lost. On your gauge you will see minor fluctuations that are normal. An extra few degrees of operating temp might be visible with a hot thermostat, which the later style gauge would hide.

A few of us have had success running slightly cooler thermostats for improving temperature control in hot weather. If other checks don't turn up obvious problems this could be something to try.

As others suggested - if the car sat 10 years be sure to replace the timing belt.
Thank You. BIG HELP. I took out the thermostat and let it idle when filling it back up with water, however when taking it for a drive the needle did not rise from cold. All hoses were hot, which is fortunate as the bottom hose was not with the thermostat was in it. The thermostat was also faulty, time for a 80 degree one. Do you know where I can buy a genuine one or any other brands that you would reccomend?

Also I will replace the timing kit, but new to the whole D24 thing, not sure to get one of those either. I am going to get a new temp sensor as it may be covered in gunk from sitting for those 10 years. Then top it all off with silicon hoses.
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  #6  
Old 04-17-2018, 09:04 PM
VolvoGabe VolvoGabe is offline
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Quote:
Originally Posted by v8volvo View Post
If the temp gauge stopped working at the same time that you replaced the tstat, possible there is an air pocket in the system. Good idea to make sure all air is bled out since this will also cause overheat if the pocket is large. Another possibility is that the wire got pulled off the gauge sender (at front of cylinder head just ahead of #1 glow plug) if the wiring harness that runs near the tstat housing got moved during the work.

90 degree tstat would be a little warmer than stock, 87C is the OE temp. 3C might be enough to make a visible difference on the gauge, these are quite sensitive. If the car had no thermostat installed when you got it, that's a clue that the warm running you are noticing was going on for a previous owner too. The plugged radiator could have been a cause, good that you found that and fixed it.

I would start by checking the electrical connections to the temp gauge sender and making sure the cooling system is well burped, then see what happens. First of all you need the gauge to work. If all the wiring appears OK, you can test the circuit and the gauge by grounding the connector for the sender. The gauge should read full hot with this wire grounded. If it does but you still get no reading when it is connected to the sender, then the sender is the issue (rare). If you get no reading when the wire is grounded, then the issue is with the gauge/cluster (rare) or a wiring connection somewhere between the engine and the dash (common). If you get to this point with no clear answers, reply back here and we can give some tips on further steps.

One factor with your 1983 model is that your temperature gauge shows variations in temperature around the operating set point. 700 series Volvos from late 1984 onward introduced "damped" dummy-style temperature gauges where the needle stays right in the middle for any temperature relatively close to operating temp, roughly 180F-210F. With those later gauges, the only time you see it move up is after a problem is already happening, so the early warning an accurate gauge provides is lost. On your gauge you will see minor fluctuations that are normal. An extra few degrees of operating temp might be visible with a hot thermostat, which the later style gauge would hide.

A few of us have had success running slightly cooler thermostats for improving temperature control in hot weather. If other checks don't turn up obvious problems this could be something to try.

As others suggested - if the car sat 10 years be sure to replace the timing belt.
Also what are some signs the timing belt needs to be replaced. It starts turn of the key every time, and it does not smoke on idle and runs very smooth. Thanks
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  #7  
Old 04-17-2018, 09:07 PM
VolvoGabe VolvoGabe is offline
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Sorry, I forgot to add the heater has been bypassed. Why? I don't know, was done by previous owner as it was a farm car and since he's 92 and in a rest home I didn't get to meet him as the car was sold on behalf.
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Old 04-17-2018, 10:35 PM
ngoma ngoma is offline
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Quote:
Originally Posted by VolvoGabe View Post
Also what are some signs the timing belt needs to be replaced. It starts turn of the key every time, and it does not smoke on idle and runs very smooth. Thanks
Only sign is the engine will suddenly quit running. Upon further inspection you will find at least bent valves, damaged pistons, probably bent connecting rods as this is an interference engine. Therefore the 65,000 mile timing belt change spec. Note that if it has sat several years in the same position that can cause a "set" in the belt that may result in a premature (in miles, not chronological) failure. So if you don't know the history of the Timing belt, better change it. Requires special tools and knowledge, sorry no way around that. Lots of info on that in this forum if you look for it.
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Old 04-17-2018, 10:39 PM
ngoma ngoma is offline
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Sorry, I forgot to add the heater has been bypassed. Why?
People often do this to temporarily "fix" a leaking heater core. What color and KPa marking does the coolant overflow bottle cap have?
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Old 04-17-2018, 10:43 PM
ngoma ngoma is offline
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Quote:
Originally Posted by VolvoGabe View Post
Then top it all off with silicon hoses.
Can you get ones for the narrow hoses on the top of the engine? And the lower radiator hose? I would be interested in these also!
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