Weird overheating issues
 

I have a 2005 G35 coupe. We got into a finder bender (hit the gal in front of us) but we were able to drive about 20 miles then the car overheated so we pulled off the interstate. After waiting 2 plus hours for a tow truck, I gave up. It was 52 degrees outside and 1AM so I started the car jumped up to 80MPH and cut the engine, popped it into neutral and coasted down to 15 and started the engine again and back to 80. I did this until the first exit which was 11 miles. Coasted into a gas station and tried to put water into the radiator but it was full of holes. We left the car there and caught a ride with a neighbor.

The car was towed the early morning, drove the car off the flatbed and into the garage. 1 more short 800ft run then we installed a radiator from my 2003 G35 for testing.

The engine runs smooth and strong but it overheats in about 2 miles after warmup.

I got a head/block tester and once the engine warmed up I started testing as per instructed. Within a minute the water was boiling hot and spurting out of the radiator like crazy. Yet the gauge in the car said it was at normal temp. The water was so hot that it started melting the testing kit.

I got my point-n-shoot temp gauge and pointed it down in the radiator and it read over 340 degrees but when I pointed at the head and block, it was about 270ish. I turned the car off and 3 minutes later I pointed it in the radiator again and it was back down to 178 degrees and so was the head and block.

One other note, last night I ran the car for 30 minutes with the water popping out of the radiator WHILE keeping the hose with fresh cool water refilling the radiator the entire time. The gauge in the car stayed at normal as long as I kept the hose refilling. But, if I took the cool water away the temp rose.

This is so weird to me, the engine runs smooth and strong but this heating issue is baffling the crap out of me. I cannot tell the insurance company what my plans are until I figure out this issue.

Tomorrow I will go a compression test.

Any other suggestions?

Michael.

Sounds like could be an issue with air in the system.
Have you also verified the cooling fans come on? - Considering the front end damage

https://cimg5.ibsrv.net/gimg/g35driv...56cc7952e7.jpg
I thought it might be air in the system but after 30+ minutes of trying to fill it, I gave up. And yes, both fans are working correctly.

The attached picture was taken before I swapped the radiators. The video is while I was adding water for 30 minutes.

https://cimg5.ibsrv.net/gimg/g35driv...56cc7952e7.jpg
I thought it might be air in the system but after 30+ minutes of trying to fill it, I gave up. And yes, both fans are working correctly.

The attached picture was taken before I swapped the radiators. The video is while I was adding water for 30 minutes.

The video is an mpeg4 so I had to zip it for this site.

I have the same issue my heater valve broke leaked a lot of coolant out.. I replaced it and now the heater doesn't work and it overheats. The fans do work. My poor car just sitting there ��

I tried raising the car up, pouring the coolant slowly,rev it ,bleed it with the heater valve,repeat ... and nothing.

Air in the cooling system is generally our issue causing over heating!
 

When you can't drive your cars and they're just sitting maybe it's time to have a professionals take a look. Any time I couldn't figure out over heating issues I've always gone to radiator shops for the fix! Gary

Maybe take the thermostat out and put it in some boiling water to make sure it works? I've bled my system several times and have never had air in the system cause it to come shooting out of the radiator like in your vid.

I'd do the compression test and see what kind of results you get. I'm wondering if the head gasket is shot, since it was driven with a broken radiator after your accident and when you go to the gas station. You can try a leak down test afterwards as well.

I would do the easiest thing first - get the front end of the car way up in the air, start and run the engine while keeping the coolant topped off in order to bleed any air from the system. This: is an invaluable tool for bleeding cooling systems. Next, test your thermostat in boiling water to make sure it's opening fully and at the correct temperature. If that's not the issue, get a cooling system pressure tester and test the cooling system to make sure it's holding pressure - that should tell you if you have a head gasket issue.

I was having issues with my G35 after my radiator had holes in it. I replaced the radiator still overheated, the thermostat 3 times still overheated, the water pump and then the fans. It still overheated. I went to autozone looking for coolant. I picked up some peak antifreeze. Well there was a chart that showed me my G35x took pentofrost antifreeze for cast iron engines. So I bought some Pentofrost. As soon as I put the antifreeze in my hot meter never rose past 3/4 the meter. For about 3 weeks now my thermostat reader hasnt moved pat the half mark.

Yes Michael!

Why have you not consulted and followed the cooling troubleshooting steps in the FSM?

http://www.nicoclub.com/service-manu.../Coupe/2005/co


See page CO-6

Telcoman

You most likely still have some air in the system. Best way to fill the system is to take the upper rad hose off the radiator and pour the coolant into the hose, filling the block first. Once you bend the hose (still connected to the block) up, it becomes the highest point of the cooling system. Once you've filled it up the the point that you can see the coolant, put the hose back on the rad and fill up the rad the rest of the way.