Coolant System Overheating--See Details

[Erik227]

My 96 RMW has been overheating after about 10 mins of driving.

The problem started a few months ago when I noticed a crack in the radiator. I did a coolant flush and I replaced the:

-Radiator -thermostat

After checking for leaks, I noticed the air in the system and bled it out, but it would still get past operating temp when running more than 10ish mins. I assumed I got a bad thermostat and replaced it under warranty

-thermostat again -coolant tank and cap -coolant flush -coolant flush again

The problem was still there, so I spent a total of probably 5 hours bleeding the air out of the system but it made no difference-air was still in there. I tested the cooling system using the exhaust gas tester shown in the video a few times, and I got some green bubbling once. Thinking it was the headgasket, I went ahead and replaced both headgaskets and had the heads resurfaced and pressure tested at a reputable machine shop

-headgaskets -water pump gaskets -upper and lower rad hoses -coolant flush

Yesterday, I decided to replace the radiator just because that’s when the issues started

-radiator again

Still no dice. Today I replaced the water pump and tested the thermostat in boiling water

-water pump & gaskets

Here is a video demonstrating the issue

Any input is welcome. Thanks!

 

[HotZ28]

Do you have the towing package with the big manual fan, or the twin electric fans? Are the fans running as designed?

 

[Erik227]

Do you have the towing package with the big manual fan, or the twin electric fans? Are the fans running as designed?

The electric AC fan is connected properly but the compressor is unplugged right now. The mechanical fan is operating with both shrouds.

 

[Erik227]

The electric AC fan is connected properly but the compressor is unplugged right now. The mechanical fan is operating with both shrouds.

Yes I have the tow package

 

[HotZ28]

So, it was not overheating prior to the radiator & thermostat replacement? I suppose the replacement thermostat was 180° F as the original and installed with the spring facing down? What brand of thermostat are you using? Have you verified the coolant temp with a scanner, or IR temp gauge to see if the inside gauge is reading correctly? Did you install a new cap on the plastic coolant tank?

 

[Erik227]

So, it was not overheating prior to the radiator & thermostat replacement? I suppose the replacement thermostat was 180° F as the original and installed with the spring facing down? What brand of thermostat are you using? Have you verified the coolant temp with a scanner, or IR temp gauge to see if the inside gauge is reading correctly? Did you install a new cap on the plastic coolant tank?

No, did not have issues with the car until the thermostat was replaced. Yes, it is installed correctly, took it out & checked yesterday. IR temp gun shows that the housing sits between 150 & 160 when it's warming up, then when it starts overheating it jumps up to about 190+, then drops back down to around 150 & repeats. Replaced the overflow cap with an 18lb one, no difference.

 

[Erik227]

Fixed

The thermastat that the shop ordered was incorrect. That explains why the issues started after the new stat/radiator install, and why the warrantied unit didn't change anything.