thewrai6th

I'm 99% sure that I have a blown head gasket, but I wanted to run it by the forum members before I do the work because there are no other symptoms of a blown HG.

My upper radiator hose was swolen 3x the normal size, so I figured it was old and I would just replace it. When I went to bleed the system, it was not filling normally. Revved it up a bit and coolant shot out of the radiator.

There is no other way for cylinder pressure to enter the cooling system unless there is a blown head gasket, correct?

3rdtimecharmer

thermostat stuck?

808zrk

Are you over exaggerating when you say shot out? I'm assuming you're talking about it shooting out of the radiator cap w/o the cap on correct? Signs to see if you have a blown head gasket are white smoke from exhaust, and dropping coolant level with no external leaks from your coolant hoses,cap etc. I'm pretty sure you know that though. When I change my coolant I rev my car to warm it up and get the air out and the coolant level rises/spews out, I always thought it was normal..

thewrai6th

I revved it to maybe 2500 and it shot up about 6 inches...
I was getting some disappearing coolant, but thought it might have to do with the expanded hose.

wunfstgsr

Thermostat.

808zrk

if it was the thermostat he would have overheating...

fcm

You do not have to have "white smoke" to have a blown HG, it depends on how/where the gasket blows.

Reving the engine will speed up the water pump and coolant will come out of the rad when cap off, how high it "shoots" out will depend on a few things, starting with amount of coolant in the system.

A HG that has blown into the cooling "jacket" will show "bubbling" in the rad at all times, [no matter what the RPM is].

A simple HC, [hydrocarbon] kit from an auto parts store will confirm/eliminate if HG is blown or not.

Lots of air in the coolant system will also "shoot" coolant out of the rad as it escapes. 94

DirtyDA9

I 2nd fcm.

thewrai6th

I'm going to check it and bleed it again. I'm pretty sure there were more bubbles than normal at idle, which is why I revved it up in the first place. I might as well just do a leakdown test while I'm at it.

Thanks for the advice everyone!

johnsc2235

Check for Hydro Carbons in the coolant, You should not get any ppm of HC, either in the overflow tank or thru the radiator itself with a cv boot on top, test it with a 5 gas analyzer...Thats how we test for blown headgaskets at our shop. I've had coolant blow out like you are saying and it was not the headgasket, it was just a plugged radiator, replaced the radiator and fixed the issue, drove the car another 90K before I sold it...

thewrai6th

^^^ This... I hope.
I thought it was not bleeding properly because I didn't drain it completely, I just replaced the upper hose. I should have thought of that. It was likely air bubbles shooting the coolant out.
Been driving it for a week, just got it smogged, no overheating or cooling system issues. No bubbles with the rad cap off.
As far as checking for HC in the coolant, it probably needs a couple flushes to get the HC out from the last time the HG blew.