Bill Dearborn

Howie,
With stock ECM settings it is almost impossible to overheat the engine to the point that you could cause engine damage. As soon as the coolant hits a certain temp the car goes into limp home mode and only fires on a few cylinders at a time to keep the engine from overheating. That is what happened to the LG car in the Forza Challenge TV show a couple of years ago. It was running away from everybody else on the road course and then the thermostat stuck and it went into limp home mode and slowed considerably. I didn't see anything in your post about suddenly losing power.

You need to clean the radiator and condenser fins and maybe replace the radiator or have a shop rod the core to clean out any blocked tubes. Also check the seals around the sides of the condenser to make sure they haven't blown away or fallen apart. On my C5s I had to put duct tape on the edges of the condenser to keep the air from blowing past it and past the radiator. On both cars those seals blew out after a few track events and they did affect coolant temps.

By the way what was the oil temp? I usually pay more attention to that than the coolant temp.

Bill

Dirty Howie

Thanks. I really don't know how cowl hoods work???


DH

Dirty Howie

Bill

I think I felt a loss of HP from timing being pulled. But it wasn't limp home mode. Car still chased down a 996 Porche when DIC warning came on. Car also ran fine on following sessions until I got DIC warning and pulled off track. No coolant overflow either, which someone said I would have seen, and suggested that my sending unit was wrong and temps were not really that high.

I definitely will at least clean radiator and oil cooler (which blocks radiator flow if it is clogged up). Probably run water wetter too. I'm thinking that dealer may not have secured shroud well and air is getting by like you experienced.

Oil temp got up to 294 which is a little higher than normal (280) so I think its all about air flow. Ambients got up to 93* but it was happening at 80* too.


DH

C5 Hardtop

Some great suggestions so far and blowing out/cleaning the Rad is the best one yet.

A long shot could be air in the coolant system if its ever been worked on.

Do beef up the oil cooler after you fix the overheating issue if temps remain that high (294 F). Once you hit oil temps north of 300 F let it cool ASAP. Engine pictures were posted a while back of a cooked LS1 where the temps hit 31xF (312 F ?, not sure exactly). Syntetic is great, but it also has limits.

Dirty Howie

The only time it was opened was when the oil pump was replaced. I think the radiator needed to be removed.


DH

jimman

Radiator needs cleaning, been there done that, same symptoms and at high altitudes it really goes nuts.

Dirty Howie

Did you just blow it out or use solvents. Removed the radiator or not?


DH

jimman

Dealer spent over an hour steaming it out, floor looked like a barn when finally finished.

Ran ok on street but could not handle hard driving and in the mountains, computer would shut off Air Conditioner and it would see 260 easy.

Dirty Howie

Did they remove it or did they do it on the car??

Thanks

BLW BY

I don't think the dic tells you when to replace the motor.

I base my analysis on your previous post about unknown metal parts in the oil, then a oil pump.
The pump is the heart and the oil is the life's blood. You replaced the heart and found foreign objects in the blood and now it's running hot.

If you kept your foot in it, would it have run even hotter?

Did it have the ability to cool back down to your normal operating temps if you were to only put 1/2 your foot into it?

These 2 questions can help figure out if you try to solve the easy fix or look deeper.

Too many times I went the easy route, when finding unknown metal debris and found out the hard way.
I even went as far as taking a magnet to find out if the metal was ferrous or nonferrous? Carbon steel or case hardened? Like it mattered.

Just don't rule anything out, the suggestions on here are maintenance related anyway and should be done to any car that is tracked.

Just my $.02

Dirty Howie

Your feedback is appreciated

The metal part was the spring seat, I posted the picture.

The car was not running hot at the track with the oil pump broken and the spring seat piece on the magnetic plug.

But it is running hot now at the track only.

Yes it cooled right down the soon as I got out of it......


DH

jimman

they did it on the car and in reponse to the dooms day guy about killing your motor. Just clicked 143,000 no oil comsumption and dynoed the same numbers as when new.

Dirty Howie

Okay, I will check and see if that service is available at my dealer. You are he first to mention this being done by steam while on the car and by the dealer.

I am going to recommend that this be a warranty issue.


DH

Z11409

I do it on all the coolers,the cleaner I use is what is on sale by the case,spray both sides ,some areas you cannot get to from the engine area.Stick hose nozzel each side of the fans.Put drip pan under the coolers and what the junk fall out of the fins.

jlvink66

If you jack up the front of the car and crawl underneath, you will see a rectangular rubber piece the full width of the radiator attached with about 4-6 hex head body screws. Unfasten the screws, pull down the rubber flap, and if you look up you will be viewing the gap between the radiator and the air conditioning condenser in front (I originally misspoke and called it the oil cooler). You blow the extended nozzle into this area and all kinds of crap will come out. I have found that it is mainly race track debris.

Secondly, I would heed the advice of some of the folks that cautioned you about the number of road & race miles on your motor. Nothing to do about heating, but you might consider freshening up the bearings/valves before it is too late.

I have been warned by many and I only have 22k miles and 26 race days.

John

Dirty Howie

Okay, so you can access from the bottom. And I know how to remove the piece on top as well, so it should easy with the right wand. Somewhere I saw someone post up the part to buy. I need to get the right one. Some are saying they used solvents/cleaners and washed while you and others just say to use air. Not sure what to use. I know too much pressure of either can bend fins.

I just bought almost new oil cooler which I am going to install as well.

I have heard to warning too .........


DH

Painrace

Take the air dam off and you will reduce front end lift on the track. You will also reduce cooling air to the front brakes slightly. To improve cooling to the brakes install a front splitter with the cooling ducts to the brakes. If you install the splitter you should also install a full width spoiler to balance the car.

My bet would be to clean the radiator area.

Jim

BLW BY

They wouldn't put a 100,000 mile power train warranty if it wasn't up to the task.

Remember an OEM oil filter doesn't actually filter the oil, it attacks the dirt to the paper media and the bulk of the oil passes through the by-pass unfiltered and back into the motor.

GM recommends you replace all the fluids before and after a track event.
That's 2 times. How many of us do that? Not to mention they're not just talking about just oil, ALL FLUIDS

This advice came from the peoples that actually made, designed, and even tracked the car before the first one ever was sold.

Why do you think, at GM's discretion, they can void your warranty if you track the car. I'd kinda keep it quiet about the -----.

Dirty Howie

What is the normal running coolant temp supposed to be (thermostat temp) 192*, 194*, 196* ???

Is there a test to determine if the water pump is working properly?


DH

Pontiaker

man so far just about everything you mention in your posts is wrong.

Just because a car overheats does NOT mean the engine is junk, probably perfectly fine after it cools down. Plus Howie said it was running hot, not truly overheating, two different things entirely.

Second the oil filter DOES filter the oil, the bypass only opens when the filter is clogged inside.

You can take this as my opinion but I was also a Tech at new car dealerships for over 18 years, started on the Corvette/Camaro line in 1989.

Howie, did they replace or drain your coolant when they did the oil pump? If so I would say there is an air bubble in the system and would make sure its completely full.

The front splitter does not bring the air into the radiator the air dam does. its the larger black plastic piece sticking down closer to the engine and it is the part that directs air into the rad/condenser. look and see if its still there, broken or warped.

Also if this problem only started after the oil pump work I am about 95% sure it has to do with something they did. Even with a clogged system it normally creeps up on you but you did say you didnt really pay attention to it before this. Could have left or installed some of the fan shroud stuff, seals, etc.Good luck with finding the problem, let us know what happens.
Matt