My "baby" is in the hospital

[dsinclair]

My poor Mark VIII is sitting up at the corner gas station (under the care of a trusted mechanic).

I have this great fear that I blew a head gasket - but he seems to think differently.

What's happening is that as the coolant comes up to temp - and the thermostat opens - it rushes headlong toward the poor plastic reservoir and spits up through the 18psi cap. Within two or three uses the car asks for more coolant.

Might be:

1.) A blown head gasket that is forcing cylinder pressure into the cooling system - thus creating a big SWOOSH as the T-stat opens (my fear)

2.) A blockage in the radiator that is causing the water pump to send too much coolant toward the reservoir instead of the radiator.

Michigan isn't that hot - so the temp gauge is stable - plus once it spits up - it settles down and runs great.

I'll know tomorrow - and either be really depressed - or really happy.

 

[Joeychgo]

Not cool --- no pun intended - Hope it works out alright.

 

[MonsterMark]

I fear you have a head gasket leak on the drivers side. Pull the plugs on that side. If one of the plugs looks really clean or the insulator is really white, that is your bad cylinder. Has the car ever overheated? Maybe a month or two ago?

 

[dsinclair]

It's gotton really warm - enough to turn on the nag screen but not peg the temp gauge, turn on the failsafe mode, or loose power, or go clicky-clack.

But yes - she got hot when the old thermostat stuck. I replaced it the next day.

Why do you say driver's side?

 

[unstoppable]

I hate to say it but I have experienced the exact same thing.Have him pressurize the cooling system.They make a cap that goes on in place of the stock one and has a hand pump on it.

 

[dsinclair]

Just got a call from the mechanic. Pressure tested it cold - then pressure tested it hot. No leaks detected.

He's kind of baffled. Oil clean, Trans fluid clean, coolant clean.

He suggested I drive it for a week and DON'T TOUCH the radiator cap - and then bring it back for an inspection.

If there's a breech in there - it must be attached to an on/off switch. (!)

I can sure make it burp up - but he couldn't with the test equipment attached.

Vacuum? Persistant air trapped in the cooling system? Did my car sneak out for a gastric bypass? I don't know...

Hmmmm...

It happens right when the thermostat opens - and only when the car is rolling down the road.

Time for the Voo-Doo doctor...

 

[Joeychgo]

I dunno Dave --- these things can get a kind of vapor lock in the cooling system......... Maybe try having the cooling system flushed --

 

[dsinclair]

Just picked up the Mark. The mechanic left word for me to not TOUCH the radiator cap or the cooling system.

He said if I get a nag screen - come in and see him.

I suspect he purged all the air out of the cooling system mechanically and also added some leak dye (or whatever they call it). Now that he's established a baseline - he doesn't want anybody to screw up his work.

Didn't charge me anything either. I paid for an oil change (always good insurance) and I know he fiddled with the cooling system for a good two hours. Nice place. :steering

 

[MonsterMark]

The head gasket leak starts out very slow at first. I agree whit Chris to replace the cap. But I still think you should pull some plugs and take a look. Your mechanic could also stuff a sniffer up the exhaust pipes to detect any radiator fluid.

As far as the drivers side, the 3 cars I am aware of that had head gasket leaks were all on the same side. Dennis even came up with a solution to make sure that side gets a little more cooling than is in the current design.

When I bought my pristine '98, the coolant light came on. After adding some water, it came on again after about 500 miles so I figured the guy dumped the car on me because he had a head gasket leak. New cap and no more disappearing coolant so I hope that that is it.

 

[Joeychgo]

cant hurt to pull the plugs -- when did you change them last? maybe do a tune up while your pulling them anyway... after all, it is spring.......

 

[dsinclair]

The plugs are likely original - 60K. I bought some 22s and if I get brave enough to yank the coil on plug wires - without ripping something loose - I'll do it soon.

Unfortunately, I'm back where I started from on my cooling problem. Once I got to the mechanic he admited to not being able to "recreate" my problem in the shop. He topped off the coolant and told me to come back when my nag screen hit.

6 miles later - "add coolant" - I also heard a "sizzle" at the radiator cap when I finished the ride.

How then could he have tested both hot and cold and got no pressure leaks? Is it as simple as a bad cap? Or a crack in the lip of the tank?

WHAT is causing the pressure to build when driving - but NOT when in the shop sitting still - even with the same engine RPMs?

WHY didn't that bum mechanic test for gases in the coolant?

I hate knowing more than the techs - and not have the equipment to do the job myself.

 

[Joeychgo]

ok, try this....... I dont know if this will work, but I ahd a similar probelm.

First, top off the coolant from the engine center fill tube. Then fill your resoivior <SP?> to the line. Now get a new cap.

Do all that........ and watch the coolant level in the resoivior -- fill it to the line if it drops. I ahve a suspicion your problem will be gone in a couple of days.

If not, your out nothing.

 

[doctorj]

I hope you have a good mechanic, I wish you luck, keep us posted

My poor Mark VIII is sitting up at the corner gas station (under the care of a trusted mechanic).

I have this great fear that I blew a head gasket - but he seems to think differently.

What's happening is that as the coolant comes up to temp - and the thermostat opens - it rushes headlong toward the poor plastic reservoir and spits up through the 18psi cap. Within two or three uses the car asks for more coolant.

Might be:

1.) A blown head gasket that is forcing cylinder pressure into the cooling system - thus creating a big SWOOSH as the T-stat opens (my fear)

2.) A blockage in the radiator that is causing the water pump to send too much coolant toward the reservoir instead of the radiator.

Michigan isn't that hot - so the temp gauge is stable - plus once it spits up - it settles down and runs great.

I'll know tomorrow - and either be really depressed - or really happy.

 

[dsinclair]

Hey I look at it this way. If I have to go inside - maybe it's time to toss the motor in there and start on the Cobra motor...

Hmmm...

 

[Joeychgo]

lol thats the right attitude --- its an excuse for that extra 100 hp

 

[rywegh]

Had a similar problem on my Cutlass. Turned out to be my Intake Manifold gasket was leaking. HAd to have it replaced no problems since. I have since found out that there is a class action lawsuit pending against GM for their use of Dexcool(orange coolant), Seems it gunks up in your system and blows out your intake gasket or jams the water pump.Nice huh! :give

 

[dsinclair]

I had a Cutlass that woofed a manifold gasket as well. One of the few times I had a clear warranty claim - and I hadn't modified the car prior to it's illness.

 

[Topcat]

There is a very simple head gasket test , to answer your question ,.If the pressure is building in the radiator , due to leaking combustion , there is a tool , that you add an inch blue liquid into a clear container . Attached to this container is a hose with a squeeze bulb on it . The end of the container is placed over an open radiator cap ,main , not the fill bottle , on a hot and circulating cooling system . The bulb is squeezed and gasses from the radiator is sucked into the liquid , no fluid from radiator , just gasses. If the blue liquid turns yellow there is a blown head gasket if it stays blue you should be looking elsewhere...
This test is capable of finding small head gasket leaks , you are talking a sizable leak to cause your situation , the test should be conclusive .. If you ask around part houses , or Mac or SnapOn or Matco ,you might even buy the tool , about $40.00 in N.Y.

 

[driller]

I remember that test kit. A long time ago, we used one to check an elusive overheat problem at work. What we found was not a head gasket, but a perforated radiator. We suspected a head gasket, but after the test results we pulled the radiator for cleaning/testing.

The hole(s) were so small(corrosion), somehow during cooling down, air was sucked into the cooling system through these holes at the bottom of the core. Any coolant loss was very minimal since in was only a temperature specific leak, the coolant would evaporate almost instantaneously. It was found at a radiator shop 'tank test' where they submerge the whole radiator.

 

[MonsterMark]

I remember that test kit. A long time ago, we used one to check an elusive overheat problem at work. What we found was not a head gasket, but a perforated radiator. We suspected a head gasket, but after the test results we pulled the radiator for cleaning/testing.

A pressure test always makes alot of sense. Especially with these cars now 11-6 years old. Good place to start I would say.

 

[unstoppable]

Okay I just dealt with the EXACT same problem.
Pressure tested at 18 LBs, left it for 5-10 minutes came back and it dropped maybe half a LB.

Oops, before I did this I removed the thermostat.I was removing variables.

Two different new caps didnt help.Actually removing the thermostat slowed down the problem.It didnt push near as much water out, but it was still hissing when I shut it off.

What I did was used a product called K@W Block sealer.Its available at all parts stores.You completely drain and flush the system of ALL antifreeze.Then mix this stuff with 3 pints of HOT water and add it to the radiator, start the car and add enough water till its full and put the cap on and let IDLE for at least 30 minutes, I did 45.Then drain it all out and leave the drain open and both caps off for 24 hours.Then flush it till ALL of the copper colored stuff is gone.( I had to flush mine 5-6 times till it was all gone)
Then test her out. I would strongly suggest new plugs at this time cause three of mine had a ton of rust on them.Thats why I didnt bother with the blue dye test thingy, I knew it was blown.

I have since driven the piss out of it and no hissing, no loosing coolant out the cap at all.My sensor is bad so it keeps telling me to add coolant though, I get out and the damn thing is full.

Sinclair, if you need any further advice feel free to ask away.

 

[Ken Nevins]

Headline: NEWBY BLOWS HIS GASKET???

My poor Mark VIII is sitting up at the corner gas station (under the care of a trusted mechanic).

I have this great fear that I blew a head gasket - but he seems to think differently.

What's happening is that as the coolant comes up to temp - and the thermostat opens - it rushes headlong toward the poor plastic reservoir and spits up through the 18psi cap. Within two or three uses the car asks for more coolant.

Might be:

1.) A blown head gasket that is forcing cylinder pressure into the cooling system - thus creating a big SWOOSH as the T-stat opens (my fear)

2.) A blockage in the radiator that is causing the water pump to send too much coolant toward the reservoir instead of the radiator.

Michigan isn't that hot - so the temp gauge is stable - plus once it spits up - it settles down and runs great.

I'll know tomorrow - and either be really depressed - or really happy.

 

[Ken Nevins]

Headline: NEWBY BLOWS HIS GASKET???

My poor Mark VIII is sitting up at the corner gas station (under the care of a trusted mechanic).

I have this great fear that I blew a head gasket - but he seems to think differently.

What's happening is that as the coolant comes up to temp - and the thermostat opens - it rushes headlong toward the poor plastic reservoir and spits up through the 18psi cap. Within two or three uses the car asks for more coolant.

Might be:

1.) A blown head gasket that is forcing cylinder pressure into the cooling system - thus creating a big SWOOSH as the T-stat opens (my fear)

2.) A blockage in the radiator that is causing the water pump to send too much coolant toward the reservoir instead of the radiator.

Michigan isn't that hot - so the temp gauge is stable - plus once it spits up - it settles down and runs great.

I'll know tomorrow - and either be really depressed - or really happy.

Hi dsynclair:
Well, I'm a new guy over here in Blissfield, MI, not too far from the Grosse Pt. and we have a '94 MK VIII that exhibits similar overheating symptoms.
Recently, starting out from a cold start, the car warms up kind of slow, with the temp. gauge resting near cold, until you hit about 5mi. out, and then the guage goes up, and up, and up, fairly quickly until it almost pins the guage and the annunciator gives warning! About the time you panic and start looking for a place to pull off, it suddenly goes back down to normal or below for the rest of the drive and no further problems are experienced until you start from cold again. I had to take the car in for an AC compressor replacement (poorly cast manifold, but that's another story!) so I asked the garage to check for overheating. With the new compressor installed, trying out the car, they did experience the overheating. Bringing the car back in, they ran the yellow/blue test for hydrocarbons in the cooling syst. that you referred too. It indicated a blown head gasket - which they wouldn't touch with a 10' pole "a nightmare to work on the D.O.H.C." sez they! So I brought the car home. On the way the temp. did peak, but then imediately came back down. I decided to try a new thermostat, which is what I thought it was. Nix! It still does the same thing. . . except last night I let it warm all the way up in the driveway, and it was OK! Do these things have a tendency to get air trapped and try to cool with air in the cooling system? BTW; this is a factory-new engine (out of waranty now) that we had put in last year to save my wifes (and my) favorite car! We had 165k mi. on a strong engine when a poorly installed oil filter caused a ruined lower end!
Anyway, I'm dying to hear how you came out with your MK burping problem. Ours don't burp, or show ANY other symptoms other than pinning the the gauge. I don't want to ruin the engine, so we just stopped driving it for now.
Regards, Ken in Blissfield

 

[Otus]

I'm sure it will survive

 

[driller]

...Do these things have a tendency to get air trapped and try to cool with air in the cooling system?

YES.

I have found the factory service procedure works well IF when you are filling at the crossover pipe - you do so with the reservoir cap off and continue until the reservoir is completely full to the top before pausing and installing the cap on the reservoir and then continuing to fill at the crossover with the engine idling. Now do as it says and let it get up to operating temperature.

Now the important part is to leave it cool back down - completely(I leave mine cool overnight in the garage). Now check the reservoir coolant level. IF LOW, open it up and repeat the fill procedure again! If the coolant level is high, siphon some out of the reservoir. Chances are it will be 'just right'.

EDIT - When I say 'full to the top', I mean full to the top of the opaque tank - not 'running over' the reservoir fill inlet. There is still air for thermal expansion in the top bulge of the reservoir.