# 92 Cabriolet Overheating...HELP



## falseimage (Jun 22, 2010)

So I have a 92 Cabrio and it is overheating after running for about 15 minutes. Thought it was the heater core, and that has now been replaced..still over heating. The oil pressure light is flashing ... probably because the oil is getting too hot. ...? Where is the thermostat located? In the front of the motor in the middle or somewhere else? If that's where it goes the thermostat isn't there so it shouldn't be over heating if the thermostat is taken out right? The motor sounds very good and everything else seems to be in working order...please help..this has been nothing but a big headache and money drain!!


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## teknikALLEN (Jul 14, 2010)

Seems that the oil pump may be not working. Easy fix for the mechanically inclined. 
No oil = friction heat, stress and wear on the engine. 

Oil pump ~$30, gasket ~ $7. Bentley manual ~$45... no special tools, just need time.


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## Where2 (Apr 18, 2000)

Thermostat is within the elbow of the hose running between the radiator and the water pump. You get to the thermostat by removing the elbow. Your view of the elbow from the bottom of the car may or my not be obscured by a power steering pump. While you're at it, replace the plastic elbow, and get a replacement O-ring seal. 

Another thing to watch for on 1.8L VW engines is the possibility of a defective oil cooler. If your oil filter screws onto a square box with hoses, your engine has an oil-to-water heat exchanger in the cooling system that was intended to transfer heat between the coolant and the oil to speed warming the oil up in colder months and help cool the oil in hotter months. 

I have personally dealt with an issue that appeared to be an overheating problem or a cracked head or cracked block. In reality, it was a pin hole leak in the oil-to-water heat exchanger which is located on top of the oil filter between the filter and the bracket mounted on the engine. This part runs ~$80. If your Cabriolet has one, you should be able to see it by looking down the front of the engine directly below the coolant flange on the front of the head that leads to the upper radiator hose... 


Good luck with the issues, bring us back any other questions you may have... I certainly recommend the Bentley manual as suggested above, but the advice of other knowledgeable VW folks is also useful. :thumbup:


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## teknikALLEN (Jul 14, 2010)

Where2 said:


> Another thing to watch for on 1.8L VW engines is the possibility of a defective oil cooler. If your oil filter screws onto a square box with hoses, your engine has an oil-to-water heat exchanger in the cooling system that was intended to transfer heat between the coolant and the oil to speed warming the oil up in colder months and help cool the oil in hotter months.
> 
> I have personally dealt with an issue that appeared to be an overheating problem or a cracked head or cracked block. In reality, it was a pin hole leak in the oil-to-water heat exchanger which is located on top of the oil filter between the filter and the bracket mounted on the engine. This part runs ~$80. If your Cabriolet has one, you should be able to see it by looking down the front of the engine directly below the coolant flange on the front of the head that leads to the upper radiator hose...


The fact that the oil light is blinking is what made me think oil circulation problem. I guess it depends if the light comes on when the car is not yet warmed up or when the overheating starts (oil thins with excessive heat). 

The oil pressure indicator can help diagnose your problem. When the car is started cold, the oil is thick and the pressure will be high. If it stays low when cold, below 2 Bars, it would indicate a bad or failing oil pump.

After a few minutes the oil pressure should drop as the oil heats up and thins at an idle. Increasing the engine RPMs should give a direct increase in oil pressure; > rpm = > Bar pressure.

If the oil pressure remains high as the car warms up until the oil light flashes, a plugged oil pump oil pick up may be the problem. I actually had some RTV silicon bits from the PO gasket fix caught in my pick up screen causing high pressure, oil starvation and overheating.

If the car passes the oil pressure "test", start with the thermostat. If that doesn't work, it could be a plugged radiator or bad water pump. 

The presence of oil in the coolant isn't indicated here so I do not believe he has an oil "cooler" problem. 

Where2?,
As far as the oil cooler goes, is there an easy way to test for a leak in the exchanger to avoid the the replacement cost of the cooler? Head gasket and bolts are pretty cheap.... but I would want to check for the leak in the cooler before doing the head gasket to avoid spending money on a "twofer" project if the head gasket is not the problem. Is oil cooler delete the only way to check the cooler for leaks besides out right replacement?

Allen.


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## dkfackler (Feb 8, 2010)

teknikALLEN said:


> If the oil pressure remains high as the car warms up until the oil light flashes, a plugged oil pump oil pick up may be the problem. I actually had some RTV silicon bits from the PO gasket fix caught in my pick up screen causing high pressure, oil starvation and overheating.


 Won't plugged pick-up screen lead to LOW pressure as insufficient oil is being circulated? 

I've seen this scenario with the RTF in the screen, too. You can remove the screen, then(gently) burn it clear with a propane torch.


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## falseimage (Jun 22, 2010)

*update*

wow i just was able to find this post again and update what happened.

took your advice and put in the thermostat also the coolant was special from the VW shop after changing that out putting in the new thermostat has not been over heating for six months now. ... now onto other problems


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