Ok, so my daily is a stock '89 GTU. It keeps boiling over on me for some reason. Ive replaced the radiator, fan clutch, thermostat, and the water pump isnt leaking, so i assume its still good. It takes it a while for it to actually overheat tho, it mainly just boils all the coolant out of the rad. but if i drive on it long enough the needle will go up. I just cant figure out what it causing it.

Am i missing something? why the heck does this thing keep boiling over? I gotta figure it out soon, SevenStock is comming up >_<.

 

I'm sorry to tell you this but it sounds like it could be a blown coolant seal. Look into the "bubble test." Have you pressure tested the system yet? I would do that if you haven't. Do you see bubbles forming in your coolant overflow tank? It sounds just like what my car was doing and it took me a while to figure out, because my leak was small and when the engine was cold it didn't let exhaust out until it was warm, they're tricky.

 

I was hoping that wasnt going to get brought up lol but in the back of my head i knew it could be an option. I havent had to deal with blown coolant seals on their own yet, so i dont know how it would act exactly if that was the case.

I didnt notice any bubbles, it was more just spewing out of the overflow. The other thing was that when the needle would go up, if i sped up the needle would go back down, would that matter at all if it was the seals?

The other thing is that this all started after i replaced my radiator becaues it cracked. The one i got was a low budget no name, full brass with a built in oil cooler thats not in use. One of my other concerns is that the radiator is junk and its not getting proper flow, and the oil cooler in it is taking up surface space that should be for water. Thus its not cooling properly.

 

radiator cap?

 

I assume you mean "transmission cooler", not oil cooler.
That's very common with aftermarket rads...one size fits all, both auto and manual transmission and the tranny cooler is basically just some tubing in the lower tank so it's not even a part of the water matrix really.

In other words, probably not your problem.

 

This. Get a Mazda cap. If the current cap isn't letting the system pressurize to the proper level, then the boiling point will be too low and coolant will go to the overflow too easily and early.

 

Yeah, my bad...tranny cooler is what i meant lol.

I think Pugs was right, blown coolant seals. I got it hot last night, pulled over and checked under the hood. Overflow was bubbling and so i gave it a sniff and smelled gas in the coolant. Which is never a good sign, so im pretty sure its toast. Sucks too, i was hoping to get it to make 200K, only 10K miles short.

So im just gunna sell this one and put the money towards a rebuild for one of my other FCs lol.

 

www.aaroncake.net has a cooling system diagnosis section, including how to check the coolant seals.

 

Any radiator shop can do a quick chemical test on a sample of your coolant and tell you if you have exhaust gases in the coolant. If you do not, the engine coolant seals are probably not the issue. If you do, well, then... rebuild. (Ask me how I know this.)

 

Hi

I bought fc s5 turbo II

it heat after 10 miles, when I open radiator cap the pressure is so high, that cap fly away

as I understand it is the same coolant seal.

But can someone explane what is this?

is it:

a) water seal
b) oil seal
c) side seal

how many coolant seals engine has
how to replace it?

Cheers

 

a) is coolant seal inside the motor that keeps the fluid from entering the combustion chamber etc

b)oil seal inside the motor inside the oil control ring pressed into the rotor itself

c)side seal is on the rotor itslef on the side lol