ikenmargie

Please help....the top radiator hose keeps popping off of the radiator. The previous owner changed the radiator when it did this the first time but that didnt help they thought the radiator was stopped up but it wasnt that....my mechanic uncles told us it was probably a HEAD gasket but since these cars dont really have what you would call a head we dont know what to even look for any one who has any advice could you please help us out

SureShot

I hope you replaced the spring clamps with with a screw clamps.

You might have a mis-fit radiator cap or a bad t-stat.

Amur_

Use two clamps where it pops off.

Use RTV between the hose and the neck.

theloudroom

It's possible you have a bad coolant seal inside your engine. The symptoms are quite similar to those of a bad head gasket on a piston engine.

If that's the problem, clamping the hose tighter is probably just going to make another hose pop off elsewhere.

Do a search on coolant seal. Someone has posted a way to check to see if it's bad. It involoves running the engine with the pressure cap off and looking for bubbles in the coolant.

Turbonut

iTrader: (1)

Try removing the cap on the filler neck and starting the engine with the coolant full to top. If a coolant seal has failed, coolant will come out rapidly, either gushing out or overflowing like you just turned a tap on. If it isn't a seal, it will spit out a little and the level in the filler neck will rise and fall a bit as the pump is turning and the coolant temp begins to rise.

Amur_

I'm inclined to disagree.

We don't know if the neck that the hose attaches to is 100% clean and dry. We don't know the age or condition of the hose, nor the clamp.

And, finally, I'd expect engine temps to rocket up long before a hose would pop off like that. My first 13B went due to seal failure, and I drove it like that for a while before it was diagnosed (I didn't know a thing about the car at the time) and I never popped a hose. And I can't recall ever hearing of anyone reporting a hose popping off b/c of a seal failure (keep in mind that I'm not in the FC section every day.) My current motor has been overheated something like 5 times (twice intentionally, doing the modified coolant flush) and, again, I never popped a hose.




Bubbles alone do not a blown coolant seal make. My motor does the bubbling thing and she's been going strong for about 3 years now. Gushing, geysering and generally spewing - yup, blown seal. Occasional bubbling? Sorry, no sale.

theloudroom

I'm not saying that it's 100% a blown seal, just that it is something that should be checked.



It's also not as if there wouldn't be varying dergees of severity of a leaking/blown coolant seal. He's the one who said "head gasket". That leads me to believe his question is in the vein of:

"This hose keeps popping off. I think I've got it on pretty well, but it still keeps popping off. Is there something wrong elsewhere, causing this?"

One of those things could be a bad seal, so I mentioned it. I hope, for his sake, that it's not.

NZConvertible

This is what is called a "band-aid". It does not fix the problem, it just masks the symptom (if you're lucky). The hose should not need extra clamps or sealant to stay in place. It is a bad idea.

Cooling system pressure is regulated by the radiator cap. If the cap isn't relieving excess pressure as the coolant heats up and expands then hoses will start popping off or splitting. Get a new pressure relief cap from Mazda. If that doesn't work then a failed seal is possible.

HAILERS

If it were a failed seal.....you should be seeing goobs of coolant beint ejected out and into the overflow tank. Do you?????? Check it out after a hard run with the water temp up/normal. You do have a regulated radiator cap, don't you??? One that relieves pressure???? Out that small tube at the filler neck that has a hose going to the overflow tank????

Amur_

Dammit.


You're right. My post was based on the assumption that everything else in the motor and cooling system is healthy.


Can you clear this question up for me, then? Say the rad cap isn't venting properly and the system is pressurizing until that hose pops off. If that hose is clamped in a normal and proper manner (either with a screw clamp or the stock POS) shouldn't it not be the first event to result from that pressurizing? Isn't it reasonable to expect that the coolant temps would climb significantly long before a hose would pop off?

NZConvertible

Without some form of pressure relief, even normal operating temps would result in the cooling system pressure far exceeding normal levels, enough to split or pop off hoses.

Amur_

Okey dokey. Thanks. I'll try to remember that.

ikenmargie

this is a bunch of good advice thanks...we started taking the motor apart and guess what we found antifreeze in the intake ports where the gas should be....the intake that hooks to the motor directly had a seal that was to say the least in pieces. Do you think that just the gasket between the intake and the engine would let the water inside the gas ports or is it probably a blown water seal?
Once again thanks so much everyone we are really newbies at the RX-7 but we love it and really want to fix it ourselves