First of all hi to everyone out there! my FD seems to overheat after about 25 miles, i check the rad and make sure it is topped up before i leave and after a while it just starts to overheat, apart from that it seems to run fine and hasnt lost and power. No water leaks from the car that i can see only when it gets hot it bubbles over into the overflow deposit.

Cheers
Derren

 

That does not sound good...

Any mods on the car?

Have you performed a coolant system pressure test?

Did you buy this locally or import it?


Here is a link to the FAQ thread:
https://www.rx7club.com/3rd-generation-specific-1993-2002-16/faq-3rd-gen-other-useful-links-68640/
Scroll down to the C section where you will find a few good threads on the cooling system. Start with this one:
https://www.rx7club.com/3rd-generation-specific-1993-2002-16/big-fat-fd3s-cooling-thread-571088/
and this one:
https://www.rx7club.com/3rd-generation-specific-1993-2002-16/cooling-system-flush-info-441967/

 

Thanks for the responce, I tried starting her up and seeing if i got much white smoke out the exhaust, a little came out but not much at all. I tried to see if i got bubbles in the rad, when started her up i started to add water and some small bubbles were rising but then cleared, then the water kept on rising (overflowing) and dropping, as it dropped i filled again and it kept doing the same the water would get sucked down by the pump and then it would rise again and overflow. As this was happening i could not tell if there were bubbles, or if this means the seals have gone. The fans seems to kick in ok when it gets hot. One thing that i have noticed also and not sure if it could have to do with anything the oil temerature gauge seemed to have stopped reading, it is on 0 all the time.

Engine mods are full exhaust, dump valve, hks induction kit, easy access oil filter, silicone rad pipes. I bought the car with mods already done and dont have the history to the car but this is what i can see it has.

I also have the airpump hose without a filter on it and the overflow deposit has a crack on the neck that has had a bodge fix and water leaks out if you try to overfill it.

Any info is good info, i am just praying is not the seals.

RX7Dez

 

Well that is not the best procedure for filling the cooling system and getting air bubbles out. I'd start with that and work from there. Check the links above for info on how to properly fill and bleed the cooling system of air.

 

I am doing this in Spain and stuff is a lot harder to find, so i had to make my own burb funel. Anyhow i set it all up and filled the funel up and started the engine and the water went down a bt then stayed at that level, i noticed that there were lots of small bubbles rising into the funel, it let out a couple of burbs and did take a little bit more water but not much. The little fine bubbles still were coming out as it got hot i waited untill it was hot gave it a couple of blasts n the gas and the water would go down then rise again. I then stopped the engine removed the funnel and put the tap on. i left her running a little more and gave it some more blasts and then i heard bubbles and then water coming out of the overflow deposit. I have a feeling that i might have to replace the seals. I am going to take her to a mate and get him to do a compression test and see. Any ideas on checking anythings else.

 

Your thermostat may not be opening. Try replacing it. They are relatively cheap .

 

I would replace the thermostat but also perform a coolant pressure test.

 

And a new radiator cap wouldn't hurt either. But it sounds like you've got combustion gasses entering the cooling system, which will mean a rebuild.

You can try pressure testing the cooling system (is that what you meant when you said compression test?). If you pressurize the cooling system and it starts shooting white smoke out the exhaust, then you know your seals are bad.

If you were just loosing coolant out the tail pipe, then you could use Alumaseal (a radiator sealant) to fix it up. But since the flow seems to be going the other direction, I doubt that would work for you.

Good luck man.





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