Constant Airlock

[Kai]

Okay - my mate ed who's doing all the work on my car is confounded by a problem. Basically, the head gasket hasnt gone, as far as he can tell, theres no leaking, all cylinders are firing etc but theres the bubbling behind the dash still, and it increases with revs - problem is, i'm losing coolant, but all the hoses have been checked and replaced, and the carpet isnt wet - what on earth could this be causing this?

He mooted the idea of there being a blow between the water jackets and said there was a minute amount of emulsification in the old oil - although that could have been due to it standing for a few weeks, no?

Arrrgh!

 

[CRE]

Okay - my mate ed who's doing all the work on my car is confounded by a problem. Basically, the head gasket hasnt gone, as far as he can tell, theres no leaking, all cylinders are firing etc but theres the bubbling behind the dash still, and it increases with revs - problem is, i'm losing coolant, but all the hoses have been checked and replaced, and the carpet isnt wet - what on earth could this be causing this?

He mooted the idea of there being a blow between the water jackets and said there was a minute amount of emulsification in the old oil - although that could have been due to it standing for a few weeks, no?

Arrrgh!

I'm going through the same thing. Mine's not been sitting for any amount of time though. For the past several days when I start cold it runs rough as hell until it has time to push all the air out of the way, and I'm loosing coolant with no signs of leaks at all.

Personally, now that I've got a new rad (old one did have hairline cracks) and a new rad cap (old one was venting WAY early and allowing coolant to blow out of the over flow) I'm now collecting parts to do the HG... I just can't think of anything that would cause this.

If anyone has any other ideas on what this might be I'd also be glad to hear it, but I'm sorry to say that I really think it's gotta ba a shot water jacket on the HG.

 

[Dirgle]

Have you guys elevated the front of the car while filling it? The heater core sites higher than the radiator fill cap, therefor making it impossible to get rid of the air bubble while the car is level.

If you haven't elevated the front here is a decent little write up on the SOGI site:
http://www.supras.com/06/techcenter/display.php?QID=22

 

[starscream5000]

How much coolant are you loosing? Have you tried jacking the front up real high and burping it?

Ninja Edit:: Heh, I got beat to the punch .

 

[CRE]

I don't know about Kai, but I've burped the hell out of mine.... air's getting back in. The garage at work has a ramp to exit which sits at about a 25º angle... that should be more than enough, shouldn't it?

 

[927mgtepat]

Go to a local car shop and have the flush the coolent system.

 

[Kai]

The coolant system in mine has been flushed and re-flushed 5 times now - whilst the front of the car is at a 45 degree angle too. Still no joy.

 

[CRE]

Mine is probably due for a flush, but I don't understand how that could cause this. I am running all fresh coolant, since changing the rad a month ago. Would you mind explaining?

 

[starscream5000]

No coolant leaking anywhere? Does it smell like there's some being burnt? Check the coolant hoses going to the throttle body...

 

[Kai]

with mine - theres no burning smell and no visible signs of leaking - wil try the throttle body though...

 

[starscream5000]

Do you have a diagram of the coolant lines layout? That will help a lot when tracking down the lines on the TB.

 

[GotBoost?]

After I did my hg repair on mine, using a mhg and arp studs at 80 lb-ft tq, I could still hear the gurgling sounds behind the dash, specially with a cold engine. A few weeks later I retorqued it to 95lb-ft, and the noise went away for good. Something to keep in mind.

 

[CRE]

After I did my hg repair on mine, using a mhg and arp studs at 80 lb-ft tq, I could still hear the gurgling sounds behind the dash, specially with a cold engine. A few weeks later I retorqued it to 95lb-ft, and the noise went away for good. Something to keep in mind.

That's along the lines of what I'm thinking... a tiny water jacket leak.

I've checked all my hoses, no coolant smell under the hood or from the exhaust. The only thing I'm not understanding is where the coolant's going. My engine under cover is spotless (I cleaned the hell out of it when I had it off to do my rad).

No damp carpet, no visible smoke, no coolant blown out of the over flow (I had that, but a new rad cap fixed that)... The only thing I can thing of is that I am burning coolant at higher RPM, but haven't had the chance to have someone help me with the diagnosis. Just wondering if I'd missed something, or if the HG is the last possibility.... Obviously I think it is, as I'm preparing to replace it. :nono:

 

[Kai]

Ed says he'll do mine for £175 - but this is already starting to eat into money i dont have...

 

[johnathan1]

Pressure test the cooling system before replacing the head gasket...mine would make the gurgling sound, and I thought for sure it was the head gasket, but I kept burping it, and I would get air out ach time, and eventually, after a long hard mountain run, the air collected at the top of the radiator, so I just filled it with coolant the rest of the way.

I haven't had the sound since. Also, keep in mind that a properly working, healthy cooling system will purge any air out on it's own. So if you started hearing it out of nowhere, and no work had been done to the cooling system prior to the sound...then you have a problem somewhere.

It could be many things: A leak, BHG, heater core, rad cap, cracked radiator...etc...so you need to pressure test it! When the cooling sysem is introduced to 21psi of pressure, even tiny leaks will become obvious.

 

[CRE]

When the cooling sysem is introduced to 21psi of pressure, even tiny leaks will become obvious.

Excellent advise. It's easy to forget how a tiny pinhole can cause tons of trouble when you're worried about bigger things like rodknock and BHG. Pressure testing is a good idea, I'll have to see if Checker or Advanced has a kit for rent.

I've already committed myself to doing my HG, valve stem seals, the rest of the upper seals and all the coolant hoses and thermostat.... I've got just enough cash for this much piece of mind. If there's a leak it's not going to be there for long.

 

[TurboStreetCar]

im sure uve done this, but u are turning the heat on when u burp the system right??

 

[CRE]

im sure uve done this, but u are turning the heat on when u burp the system right??

Can't speak for Kai, but I am. Thanks though.

 

[Kai]

Er - i dunno how Ed/Jesus is doing it - i would assume so, seeing as he is almost a deity in the UK Supra circle (a small band of people!)

 

[Kai]

It's been confirmed. Theres CO2 in the cooling system - the head gasket has indeed blown. According to Ed its nothing too serious and he's going to replace the gasket for me and i can 'pay him back something later', all i can say is he's a class geezer, and if anyone on the forums can give him some work (and they're in the UK), then by all means let me know and i'll put you onto him.

I still get my baby back this week though....