Not quite overheating

[chaseincats]

4 hours ago, Zed Head said:

I was thinking of blocked passages in the head gasket.

I'd probably back flush the system myself, if I was reasonably sure that everything else was right.  Push any blockages back toward the water pump and out the inlet.  Disconnect the radiator, hook up a hose to the thermostat housing (outlet port) and see what comes out.

 

I did that early on after running radiator flush through the system.  A good amount of stuff came out for sure.  Do you think its worth doing again?

[jonathanrussell]

I am sure your situation is frustrating. I read back through all of your posts and here are my thoughts.

- I am still not convinced you have ruled out whether or not you have a head gasket leak. You have multiple posts where you mention white exhaust. None of your efforts and energy are going to work if you have a head gasket leak.

- If you remain uncertain whether the thermostat is an issue....do what Zed Head has suggested and remove the thermostat as a test. If it runs hot without a thermostat then the thermostat is certainly not the problem.

- You mention multiple flushes to clean out rust in the block. Is it possible that the flushing freed up debris that is now restricting flow in the new radiator? May need to pull the radiator and flush it out with hose, etc.

- If all of the above checked out, I would come up with a way to confirm / visualize that coolant is flowing freely through the system. Might use some clear hoses, watch waterflow in the top of radiator, etc.

 

[chaseincats]

On 12/13/2022 at 9:16 AM, jonathanrussell said:

I am sure your situation is frustrating. I read back through all of your posts and here are my thoughts.

- I am still not convinced you have ruled out whether or not you have a head gasket leak. You have multiple posts where you mention white exhaust. None of your efforts and energy are going to work if you have a head gasket leak.

- If you remain uncertain whether the thermostat is an issue....do what Zed Head has suggested and remove the thermostat as a test. If it runs hot without a thermostat then the thermostat is certainly not the problem.

- You mention multiple flushes to clean out rust in the block. Is it possible that the flushing freed up debris that is now restricting flow in the new radiator? May need to pull the radiator and flush it out with hose, etc.

- If all of the above checked out, I would come up with a way to confirm / visualize that coolant is flowing freely through the system. Might use some clear hoses, watch waterflow in the top of radiator, etc.

 

All makes sense.  Since I did a leakdown test and didn't see any bubbles in the radiator & used a combustion gas tester, how else would I check for a head gasket leak if there isn't any mayo in there either?

[Zed Head]

 

On 12/11/2022 at 5:42 PM, chaseincats said:

I have not tried the new thermostat in the car because driving it around in this cold weather won't give me a definitive answer, but I am feeling confident that my old worn-out OEM thermostat not opening at the right temperature (and not to the right amount) started this issue, and installing an aftermarket thermostat that physically can't move as much coolant as an OEM one kept me heating up, but for for a different reason entirely.  With the new OEM thermostat correcting both issues, we should be all set come spring time.

I don't see any progress until spring.  You seem confident in what you've done.

[chaseincats]

33 minutes ago, Zed Head said:

 

I don't see any progress until spring.  You seem confident in what you've done.

I agree with no definitive answer until then.  I will post some observations in the interim though.

[chaseincats]

On 12/15/2022 at 6:32 PM, Zed Head said:

 

I don't see any progress until spring.  You seem confident in what you've done.

We won't need to wait for spring, the thermostat didn't do anything different except drop the temperature noticeably faster when going from 180+ at idle down to 170 when driving.

I did notice that when I held the idle higher than 800, the temp would drop slightly so I grabbed some cardboard and slowed down the fan to see if I could spin it backwards and I could a tiny bit but then it went right back to how it was supposed to run.  Here's a video from just now.  I replaced the old fan clutch (Aisin) with a new Aisin clutch when this started about a year ago and I believe they both worked the same way when spun backwards.

So I'm assuming we're moving back to rust in the block is clogging the radiator?

[Zed Head]

29 minutes ago, chaseincats said:

the thermostat didn't do anything different except drop the temperature noticeably faster when going from 180+ at idle down to 170 when driving.

Can you elaborate?  It's not clear what you're saying here.  Have you run it without a thermostat yet?

[chaseincats]

7 minutes ago, Zed Head said:

Can you elaborate?  It's not clear what you're saying here.  Have you run it without a thermostat yet?

With the old smaller thermostat the car would get up to 180+ at idling but when starting from a stop (at a traffic light for example), the car would drop back down to 170 after a few minutes of air flowing through the radiator at road speeds.  With the new larger opening thermostat, it will get up to 180+ at idle but when starting from a stop with this new thermostat, the car drops to 170 within a matter of seconds - the car is cooled way faster with the larger OEM thermostat.

I have not driven the car without a thermostat because the car never had this problem with the old OEM thermostat (until 2020).  The new OEM thermostat that's in the car now was tested in a pot of water so I could confirm it was working as it should and at the proper temperatures before installing in the car.  Driving the car without a thermostat might keep it slightly cooler but that would be a bandaide and not fix the real problem.

[Zed Head]

Running without a thermostat was not suggested as a solution to the problem.  It was suggested as a diagnostic tool.  You chose a halfway diagnostic method.  

What's next?  Good luck.

 

[chaseincats]

4 minutes ago, Zed Head said:

Running without a thermostat was not suggested as a solution to the problem.  It was suggested as a diagnostic tool.  You chose a halfway diagnostic method.  

What's next?  Good luck.

 

Just so I understand, what would it running better without a thermostat or running worse tell us?

[Zed Head]

Early on you were buying and trying different thermostats.  Running without a thermostat takes the thermostat completely out of the picture.  The thermostat is a heat control device, not a cooling device.  If the rest of the cooling system without a thermostat can't keep the engine under the desired temperature then changing thermostats will never solve the high temperature problem.  

It was the fastest way to learn if the thermostat was the source of your problem.

[chaseincats]

13 minutes ago, Zed Head said:

Early on you were buying and trying different thermostats.  Running without a thermostat takes the thermostat completely out of the picture.  The thermostat is a heat control device, not a cooling device.  If the rest of the cooling system without a thermostat can't keep the engine under the desired temperature then changing thermostats will never solve the high temperature problem.  

It was the fastest way to learn if the thermostat was the source of your problem.

Gotcha.  I will be out of town so I can try this in a few weeks.  The reason I was trying to go around this is paper gaskets do not seal my thermostat housing - each time I pop it open I need to seal it with RTV.

Regarding head gaskets, one thing I don't understand is if I accelerate hard and shift, there will be a puff of white/sweet smelling smoke out of the tailpipe (coolant) but when I pressurized the cylinders for the leak-down test, there weren't any bubbles in the radiator.  Also the exhaust gas in the radiator tester with the blue liquid did not change colors either.  I don't understand how coolant makes its way into the cylinders sometimes but does not show up in any tests.

Edited December 17, 2022 by chaseincats