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Running out of ideas on overheating

Haven't reread the whole post but did the water pump get replaced recently? The pump from the early Renix 2.5L looks identical but has the impeller reversed and can cause a ton of issues. They sometimes get switched at a rebuilder.

First post says he is on his 3rd water pump. So unless he got really unlucky 3 times in a row the water pump has kind of been eliminated

The op definitely seems to be taking the parts shotgun approach without any real trouble shooting.

Me personally if I had done all that the op had done I would have pulled the head off by now. Could be something as simple as a improperly stamped head gasket to, to much rtv down one of the head bolt holes restricting the passage.
 
First post says he is on his 3rd water pump. So unless he got really unlucky 3 times in a row the water pump has kind of been eliminated

The op definitely seems to be taking the parts shotgun approach without any real trouble shooting.

Me personally if I had done all that the op had done I would have pulled the head off by now. Could be something as simple as a improperly stamped head gasket to, to much rtv down one of the head bolt holes restricting the passage.

Just waiting on new A/C stuff in the mail to convert and going to take the leap on pulling the head off. The motor stayed cool until the rebuild so you're probably right. Was hoping I wouldn't have to pull the thing apart but oh well. Have another vehicle I can drive in the mean time.
 
What did IR temp tester tell you?

Did you profile the radiator temps from the inlet to the outlet, top to bottom to look for any cold spots? What is the inlet temp and outlet temp of the radiator at idle?

Does the temp rise or fall when you increase the rpms to say 1500 to 2000 rpm from idle after say 10 mins at idle?

Is the E-Fan running?

Is the fan clutch locking up to where you can barely turn it by hand after running the hot engine, shutting if off then trying to turn the clutch fan?

If the temp drop across the radiator is about 25 degrees F or more (even 20 degrees is high IIRC), it has trash blocking the flow at the inlet, or the water pump is not pumping. Try back flushing the radiator!!!

If the temp drop across the radiator is about 5 degrees F, you are not moving enough air.


Just waiting on new A/C stuff in the mail to convert and going to take the leap on pulling the head off. The motor stayed cool until the rebuild so you're probably right. Was hoping I wouldn't have to pull the thing apart but oh well. Have another vehicle I can drive in the mean time.
 
What did IR temp tester tell you?

Did you profile the radiator temps from the inlet to the outlet, top to bottom to look for any cold spots? What is the inlet temp and outlet temp of the radiator at idle?

Does the temp rise or fall when you increase the rpms to say 1500 to 2000 rpm from idle after say 10 mins at idle?

Is the E-Fan running?

Is the fan clutch locking up to where you can barely turn it by hand after running the hot engine, shutting if off then trying to turn the clutch fan?

If the temp drop across the radiator is about 25 degrees F or more (even 20 degrees is high IIRC), it has trash blocking the flow at the inlet, or the water pump is not pumping. Try back flushing the radiator!!!

If the temp drop across the radiator is about 5 degrees F, you are not moving enough air.

The only thing that was odd with the IR temp was an uneven temp in the fuel injectors. Two of them were about 10 degrees off from the others but it could've been the angle and location. Radiator didn't have any noticeable dead spots at higher temps. Everything was reading around 200 degrees a few minutes after shut off including the radiator and thermostat were both pretty close to each other. Also my computer monitor is about 90 degrees hahaha.

Electric fan is running all the time. I check the airflow to make sure both the mechanical fan and radiator fan were blowing the correct direction. I haven't gotten a chance to test the O2 sensors yet. Birthday weekend so the wife wanted to do everything but what I wanted to do. I have the ideal ranges written on my white board.

I have the other temps written down for the radiator hoses and heater core hoses. I didn't try temping it while moving the RPMs but I'll work on it and report back. I'm waiting for my 134a conversion stuff to get in and the family time to calm down a bit.
 
to much rtv down one of the head bolt holes restricting the passage.

I have 2 things to say about that..............
RTV has business being around a head gasket or on the bolts.
Only #11 head bolt is a "wet" thread.
 
Ignore the temp difference on the fuel injectors.

Temps when the rig is off are irrelevant.

Only temp differences worth checking is when the rig is running, see the list in my prior post.

The only thing that was odd with the IR temp was an uneven temp in the fuel injectors. Two of them were about 10 degrees off from the others but it could've been the angle and location. Radiator didn't have any noticeable dead spots at higher temps. Everything was reading around 200 degrees a few minutes after shut off including the radiator and thermostat were both pretty close to each other. Also my computer monitor is about 90 degrees hahaha.

Electric fan is running all the time. I check the airflow to make sure both the mechanical fan and radiator fan were blowing the correct direction. I haven't gotten a chance to test the O2 sensors yet. Birthday weekend so the wife wanted to do everything but what I wanted to do. I have the ideal ranges written on my white board.

I have the other temps written down for the radiator hoses and heater core hoses. I didn't try temping it while moving the RPMs but I'll work on it and report back. I'm waiting for my 134a conversion stuff to get in and the family time to calm down a bit.
 
Ignore the temp difference on the fuel injectors.

Temps when the rig is off are irrelevant.

Only temp differences worth checking is when the rig is running, see the list in my prior post.

Gotcha. Little bird told me its a good way to tell if an injector is failing causing it to run lean and raising temps.
 
Gotcha. Little bird told me its a good way to tell if an injector is failing causing it to run lean and raising temps.

In my experience the front FI, #1 seems to be running way cooler than the #3 and #4 injectors and I think #5 looks the hottest, simply because of the exhaust pipe layouts next the intake tubes. When running my IR sees as much as 50 F difference IIRC on normally running 4.0s.

On some better layed out engine fuel injector set ups it might work
 
Sorry guys haven't given up yet but not much has been done. Its been over 100 degrees here and working longer hours for a time being. I'm replacing my A/C components slowly due to the heat so everything is unplugged. Putting in a new alternator and cables while I'm there. I'll report back soon as the battery is hooked back up.

ehall - New radiator cap straight from the factory. No luck. Have the system pulled apart and going to double check for any clogged parts in the radiator. It's a new CSF 3 core but never hurts to check. Also on a side note my over flow bottle had about 3 inches if not more of mud/clay at the bottom. It's been replaced as well. I'm still concerned about the fuel. I need to figure out a way to test if the injectors aren't pushing enough fuel and I believe its my wiring harness that might be causing the issue. I have a list of repairs/replacements to try and figure out why my idle is slightly off but my motor is shaking enough to rattle my doors when they're open. Even had the motor rebuilt due to some compression numbers from a leak down test. Seems like something is making it run lean and I don't think its any of my sensors but thats for another day.
 
Everything is still pulled apart so unsure. I have more crap to take out after work today including the radiator so I can get to the AC condenser. Hopefully tomorrow I'll be able to start dropping stuff back in. 104 again today so who knows.
 
Does coolant flow in and out of the overflow bottle now?

It must do that, if it doesn't you still have a fundamental problem

I agree that is an often overlooked and under maintained area. Leaking air into the line under vacuum when the coolant in block/radiator contract and cool is not obvious!!! Both the top side of the cap (not just the bottom) and the hose end to end, must be air tight, and they may not leak liquid out, but may let air go into the radiator instead of coolant from the overflow bottle on the cool down cycle.
 
Yeah there was no way coolant was getting back into the system through that mud. Not saying its the cause but couldn't have been helping either. I'm talking a solid 3 inches of clay and mud. New one has a tight cap and going to run a new line/clamps once everything is back together. Any tips on checking for a clogged radiator core while its out?
 
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