Engine not cooling

[Turpin]

Hello guys,
I'll start this by saying i noticed the engine not cooling after I changed oil from the winter mix( 15-40) to the summer mix (20-50). I use Brad Penn oil.

I have checked to make sure all the cooling tin is in place and all the other cooling pieces. I've even cleaned the oil cooler and checked the voltage at the fan located on the oil cooler.

Do you think there is something odd with the oil?

Today the weather was really nice, ~84F and engine temp was ~250F and climbing when I got home from work, which is a 20min ride.

Amy advice is greatly appreciated.

Thanks,
Russell

[ossiblue]

Have you checked to see if your external thermostat is working as it should?

[universeman]

This is new? I don't think an oil change could cause overheating...are you sure you put in enough oil (check level again?) Is your oil cooler up front getting hot?

[tdw28210]

Did an oil LINE get crushed during the change?

[Steve@Rennsport]

As you know, 250 deg F is FAR too hot so this problem needs to be addressed before you drive it again.

I would start by removing the external thermostat to check and make sure its opening all the way by 190 degrees. You can remove the element and test it with boiling water and a thermometer to see when its all the way open.

After that, check the CO & ignition timing.

Check the cat to make sure its not clogged or obstructed in any way (not uncommon).

[Turpin]

Hey guys,
Thanks for the quick replies and suggestions. It is too nice out not to drive...

That is a good thought about the thermostat. I assumed it was working because the oil cooler is hot. I will check to make sure it is operating correctly.

The oil level is good. I check it regularly and it is generally pretty close to full.

tdw28210, I don't understand your statement.

Thanks,
Russell

[Turpin]

Originally Posted by Steve@Rennsport

As you know, 250 deg F is FAR too hot so this problem needs to be addressed before you drive it again.

I would start by removing the external thermostat to check and make sure its opening all the way by 190 degrees. You can remove the element and test it with boiling water and a thermometer to
see when its all the way open.

After that, check the CO & ignition timing.

Check the cat to make sure its not clogged or obstructed in any way (not uncommon).

Steve,
Thanks for your help. I'll pull the thermostat and see what happens. Forgive my ignorance. What is CO?
I guess it is possible that the timing could have advanced. I will give that a check too.

Thanks!

[tdw28210]

Originally Posted by Turpin

Hey guys,
Thanks for the quick replies and suggestions. It is too nice out not to drive...

That is a good thought about the thermostat. I assumed it was working because the oil cooler is hot. I will check to make sure it is operating correctly.

The oil level is good. I check it regularly and it is generally pretty close to full.

tdw28210, I don't understand your statement.

Thanks,
Russell

Turpin,

I was wondering if somehow one of the oil tubes that runs along the outside edge of the tub got crushed somehow during the oil change process. A misplaced jack, lift arm or even jack stand could do it.

[pavegeno]

Mine ran hot and it was the engine mounted cooler. Assumed it was the external thermostat or FR wheel cooler but it was the engine mounted all along.

[86 911 Targa]

PM sent.

[vansicklenmi]

Check the coolant level

[Steve@Rennsport]

Originally Posted by Turpin

Steve,
Thanks for your help. I'll pull the thermostat and see what happens. Forgive my ignorance. What is CO?
I guess it is possible that the timing could have advanced. I will give that a check too.

Thanks!

My pleasure.

CO is Carbon Monoxide and one major parameter for setting fuel mixture (using a 4- or 5-gas analyzer). Make sure its set at factory timing, both at idle and 6K RPM.

Good luck!!

[Rawknees'Turbo]

Another thing to check, which I don't think has been mentioned, is to look in through the engine fan the best you can (with flashlight, small mirror, etc) to see if rodents have packed the tops of the cylinders and heads with food and nesting material . . . very common and I've even seen pics from a member where mice had covered the entire top of both banks with large, horse treat pellets.

[Turpin]

Hello guys,
I pulled the alternator and checked for rodent nests. I didn't find any nests but I did notice some gaps where the air moves into the heater hoses.

I also found out that my alternator diodes are bad.:-( So I'll a little more time to investigate the cooling issue.

I will order a CO tester. I could use one for my 59 VW KOMBI too.

Thanks,
Russell

[Turpin]

here is an update on the situations...

Turns out that the alternator is good. It was the starter causing the battery drain. Installed another starter and the battery drain went away. :-)

I did pull the oil thermostat and submersed it into some boiling water. It appeared to be working fine. I did happen to notice that the thermostat was installed incorrectly. I guess when I installed ~4years ago I connected the oil lines to wrong in & outs????

So I am guessing that the thicker oil couldn't flow as easily as the thinner oil. Plus the thicker oil carries more heat. I still have 20-50 oil in the car. I will probably change to 15-40 in a couple of months.

Everything appeared to be good on the 20min test drive.

Thank guys!

[Turpin]

Okay guys,
Here is an update on the "engine running warmer than normal" isssue. I changed the oil back to 10-40 and bam! Engine temp stays between 180&210 with normal driving.

It is very bazaar that the oil was causing the engine to run warm. It makes me wonder if something was wrong with the oil???

Anyway, anther data point

Thanks for all your suggestions and help!

[Reiver]

Originally Posted by Turpin

Okay guys,
Here is an update on the "engine running warmer than normal" isssue. I changed the oil back to 10-40 and bam! Engine temp stays between 180&210 with normal driving.

It is very bazaar that the oil was causing the engine to run warm. It makes me wonder if something was wrong with the oil???

Anyway, anther data point

Thanks for all your suggestions and help!

A 50-60 degree difference in oil temp I'd think is unusual if all things are equal....I wonder if you have some kind of restriction in your oil cooling system. A restricted oil tube, backwards sump plate...
BP 20-50 is a high viscosity....I believe it 'thicker' than say VR1 20-50 under load...but I see no real difference in temps due to that.
I just used a case of BP as I had it...altho I have been using VR1...and today ran at 185 because it was cooler this morning in the Phx, Az.it maxed at 195.
I suspect you have some other issue with that large a spread.
Do your oil pressure rredinsg remain the same with both oils...or close?

[Turpin]

The 20-50 was Brad Penn. I'm not sure about the oil pressure because my car doesn't have a gauge...only a dummy light. The car is a 69-912.
But that is a good thought. I'll install a dual press/ temp gauge and monitor the pressure.

Thanks!

[Reiver]

Originally Posted by Turpin

The 20-50 was Brad Penn. I'm not sure about the oil pressure because my car doesn't have a gauge...only a dummy light. The car is a 69-912.
But that is a good thought. I'll install a dual press/ temp gauge and monitor the pressure.

Thanks!

That is a horse of a different color and you might get a better response in the 912 section....

[Turpin]

Good point...I was looking for advice from this section too because isn't exactly stock�� It uses some 911 cooling features but with a large displacement 914 block.

Thanks again!