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Old 07-29-2011, 05:48 PM   #1
a400tool
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Question 91 Turbo Cooling Issues

My 91 Turbo (manual) has a cooling issue. When driving, temp is within normal limits, slightly less than half way between H and C. When I stop driving, the temp increases to 3/4 hot. A fair amount of cooling fluid is then passed to the expansion tank and onto the ground. After the engine cools, there is no fluid in the expansion tank and the radiator is not completely full. I have changed the thermostat and seal, upper and lower radiator hoses, the radiator cap and the fan clutch. The water pump is working, no leaks or bearing play. The radiator was replaced several years ago and appears to be in good nick.

Any ideas would be greatly appreciated before I change/upgrade the radiator and water pump.

Car is a daily driver (102k mi), no mods. Head gasket has been changed and compression on all six cylinders is within spec. No evidence of water in the engine oil.

Thanks

Last edited by a400tool; 07-29-2011 at 05:50 PM.
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Old 07-29-2011, 07:02 PM   #2
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Do you have the fan shroud (if so, is it in good shape?) or the splash guard under the engine? Both make a difference to your temperatures when the car isn't moving.
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Old 07-29-2011, 09:12 PM   #3
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After you have checked what is mentioned above, check all your hoses. A small hole in a hose may not leak coolant but instead suck in air while coolant is circulating. This will cause an air pocket and it will puke coolant out soon after. Its usually a sign of air in the system if the temp goes down when driving and up when stopped. Make sure you have the heater on when filling the system to purge the air out of the heater core.
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Old 07-29-2011, 10:55 PM   #4
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Yes, fan shroud is in good shape as is the engine under cover.
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Old 07-29-2011, 10:56 PM   #5
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Quote:
Originally Posted by El Supracabras View Post
After you have checked what is mentioned above, check all your hoses. A small hole in a hose may not leak coolant but instead suck in air while coolant is circulating. This will cause an air pocket and it will puke coolant out soon after. Its usually a sign of air in the system if the temp goes down when driving and up when stopped. Make sure you have the heater on when filling the system to purge the air out of the heater core.
I've done all that as well. I will recheck the turbo coolant hoses to be sure.

Thanks.
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Old 07-30-2011, 12:23 AM   #6
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Quote:
Originally Posted by a400tool View Post
Yes, fan shroud is in good shape as is the engine under cover.
Damn, was really kinda hoping you'd respond that your shroud was mangled or missing.

How confident are you in your fan clutch? The fluid in them can leak out over time which prevents it from spinning up properly when you're idling.

Also, have you pressurized your coolant system to see if one of your hoses has a weak but not obviously blown area?

Forgive the questions, just trying to hit all the reasonable bases before you go digging into your radiator and water pump.
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Old 07-30-2011, 04:08 PM   #7
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dude a fan shroud, while important isn't as extremely critical as all that.
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Old 07-30-2011, 06:48 PM   #8
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Maybe this will help...or scare you. It scares me..... to think of how many points of failure the cooling system on the 7MGTE has. Hope ya get it sorted out soon.
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Old 07-30-2011, 06:52 PM   #9
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Don't forget this.
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Old 07-31-2011, 01:03 AM   #10
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Quote:
Originally Posted by Green7mgte View Post
dude a fan shroud, while important isn't as extremely critical as all that.
I know, but from my perspective every little bit is a gain, and as prone to overheating as these cars are I don't write any contributing factors off.
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