Hi everyone. My 3800 turbo starts to seriously overheat after 3 or 4 laps. To the point of blowing all the coolant out through the expansion vase! On open road driving however, I never have any temperature troubles. Car runs fine - never hot. Anybody had the same problem? Is there some coolant system that I forgot to fit with the 3800? I'm using the standard Fiero radiator, pipes, fan etc... And as I said, on open road (hard driving) it never overheats. Thanks for your suggestions. Regards, Rafe
Running that car hard at the strip is going to produce a lot of heat. That is a lot of abuse then you stop the car, so it is not going to cool down like driving it around because of the airflow. When you finish your runs do you let the car idle some before shutting it down? That could help out to cycle coolant to help it cool down some. The best answer would be to upgrade your radiator to a Champion 3 core CC828.
Thanks for the reply. I think I should specify that the car overheats during the track session. Even taking a lap easy to cool down, the temperature keeps rising, once the problem starts. I have to get back to the pits and re purge / bleed the cooling system. I think I'm getting a gassing/boiling situation at the highest point in the engine coolant system? The coolant being forced out through the expansion bottle/vase is not that hot. I don't have clouds of steam etc... Is it a circulation problem combined with the cars mouvements from side to side onthe track?
Bigger radiator OK, if I really had far too hot coolant at the front. I'm thinking equivalent vapor lock in the cooling system...? Rafe
Is it road racing that you are talking about? Drag racing will not put a car/motor combination to the test but a circuit will. Maybe you don't have a thermostat? Not allowing the system to slow down the coolant so the radiator draws the heat away. IF that cycle happens too fast your engine will overheat. OR thermastat not opening fully.
I have done many track days with my Fiero and never had a problem. But since I want to concentrate on the driving and not worry about overheating I don't use water in my cooling system. I use a product called Evans Coolant. I'll leave the link below. Some of the benefits are: No pressure in the system, it will boil at 395F, lubricates your pump and will not rotten your houses and will never go bad as long as you don't mix it with water. https://www.evanscoolant.com/
[This message has been edited by La fiera (edited 06-06-2017).]
Yes its road racing. (We don't have many drag strips in France!) The problem starts on about the 3rd lap of a quite twisty race track that we use. Thanks for the tip for the race coolant - I'll look into that. As for the thermostat, I keep a thermostat. But maybe I'll drill a small hole in it - used to do that with my older cars to help keep a small bypass of cooling all the time. I think I'll investigate the thermostat never the less, and the restriction that it causes? Your 1st idea is good, but I think my problem is a lack of flow and not that there is too much flow. Otherwise, I would have super hot steam at the radiator. All I have is pressure forcing out all the coolant via the radiator cap and expansion bottle. Rafe
[This message has been edited by Frenchrafe (edited 06-06-2017).]
Sorry, didn't see the previous message. Yes, the front is stock and yes the dam is in place. Car doesn't overheat at high speeds. It overheats with hard twisty bends and short hard accelerations between bends.
Sorry, didn't see the previous message. Yes, the front is stock and yes the dam is in place. Car doesn't overheat at high speeds. It overheats with hard twisty bends and short hard accelerations between bends.
Make sure your system is properly purged. Also, in my car I took out the sensing bulb out of the thermostat and I also have a bigger radiator. Is your radiator hot all around or it has cold spots?
[This message has been edited by La fiera (edited 06-06-2017).]
Sorry, didn't see the previous message. Yes, the front is stock and yes the dam is in place. Car doesn't overheat at high speeds. It overheats with hard twisty bends and short hard accelerations between bends.
In that case, does your radiator fan turn on? You may just have a bad radiator cap that is not maintaining system pressure.
[This message has been edited by Gall757 (edited 06-06-2017).]
Yes, radiator fan is fine. Checked radiator cap while at the track, but will do a pressure test this week. I'll probably order a new one just to be sure.
[This message has been edited by Frenchrafe (edited 06-06-2017).]
I've just read the Ogres info on radiator caps and......
While fitting my new turbo recently (getting ready for the season), I had the back of the car in the air, ie nose down. What do think happened? Most of the coolant leaked past the radiator cap! I didn't pay attention at the time because too busy trying to get the new turbo installation finished... Probably that check valve was already dying! I'll be ordering a new cap and loads of fresh racing coolant! Thanks for all of your help everyone! Rafe
