please dont be head gasket!!

[chuckles_100]

I've probably put this post in the wrong place again! Any way I have a 1992 STS with a 4.9. I bought the car and after I drove 4 miles the head gasket was evidently gone so I had it towed home. Because I was crushed between 2 cars 3 years ago I had to pay a fella to do the headgaskets. I had the heads planed, all new gaskets new 50/50 antifreeze along with the G.M pellets. Car has seemed to run great. I have put around 600 to 700 miles on it. every morning I check oil and antifreeze to be sure. always at top of rad. Well this morning I checked oil and was fine and when I went to open rad cap it still had a little pressure and burbled(car was off and had sat overnight) I thought it must be ok as it still had pressure and has been ok for a month. anyway I drove about 2 miles then I noticed the temp. spiked up to 232 f! It hasnt done that since I was bringing home the first time.I pulled over immediatly and the coolant had filled the resevoir and spewed a bit out the top of it too. I put my hand on the top of the motor and it wasn't very hot at all. I removed the rad cap and looked and a/f was out of sight. I replaced it and headed for home.temp stayed fine. although warmer than it has been for me yet but today it was 52 f out and its always been about 40 f or lower so thats why its stayed around 207 I would think. When I got home It had sucked the antifreeze back into the rad and the resevoir was at the full/hot line where it should be. I was thinking that when I loosened the rad cap the first time maybe some gunk out of the rad was trapped under seal allowing a/f to go into resvoir instead of over 15 psi? I bought a new OEM cap @ 15 psi cleaned neck off and drove it on the highway for about 10 miles then immediatly in town and temp went 207 on highway and at most 217 f in town I came home and let it idle in drive way and watched gauge. Went from 203 to 225 fans came on went to 203 again. I let it do that 4 times. I drove it around town 2nite no heat up. If it blew the head gaskets again wouldnt it keep surging out of the tank? I have had heat in the heater all through this episode this time, when head gasket went first time I didnt have heat. Any help would be appreciated because my wasnt happy when I bought the car on a whim was even less happy when I had to pay to have it fixed so If it is the head again Ill never get sex again!!!
I love this sight and all the knowledge in here is amazing
Sorry for such a long post but I wanted to be sure I got it all so you could help me fix it
Chucky

[CadiJeff]

sounds to me like either your fans didn't come on or mabe air trapped in the system.

[illumina]

first, the temp will usually run around 215 during city driving. highway driving gets around stock t-stat temps (195).

when driving, do you smell any antifreeze?
have you lost any power (engine)?
i'm guessing that your oil is clean, right?
do you visably see any water from outside the car?
if so, where?

look very closely to find any swolen hoses in the coolant flow to see if there may be any type of leak. this should include the water pump and radiator area (either one may spring a leak too). pressure test the actual radiator while you're at it.

try this: when the car is at idle (make sure your radiator and recovery tank is full *full cold*), get her to warm up and see if the coolant revovery tank has any bubbling action once warm. if so, follow up with a compression test.

the other thing i can think of is there may be a leak in the intake manifold gasket somewhere. if you're smelling coolant (external leaking) or have any coolant in the oil internal leaking), the intake gasket may be the cause.

[chuckles_100]

Originally Posted by illumina

first, the temp will usually run around 215 during city driving. highway driving gets around stock t-stat temps (195).

when driving, do you smell any antifreeze?
have you lost any power (engine)?
i'm guessing that your oil is clean, right?
do you visably see any water from outside the car?
if so, where?

look very closely to find any swolen hoses in the coolant flow to see if there may be any type of leak. this should include the water pump and radiator area (either one may spring a leak too). pressure test the actual radiator while you're at it.

try this: when the car is at idle (make sure your radiator and recovery tank is full *full cold*), get her to warm up and see if the coolant revovery tank has any bubbling action once warm. if so, follow up with a compression test.

the other thing i can think of is there may be a leak in the intake manifold gasket somewhere. if you're smelling coolant (external leaking) or have any coolant in the oil internal leaking), the intake gasket may be the cause.

I dont smell any a/f when im driving or sitting idling and the oil is a perfect golden colour. Still all kinds of power too. Only a/f I seen was when some came out the top of the overflow cap. The hoses where fairly hard but not to the point of bursting. seemed fairly norm actually. I looked all around the w/p and didnt see any leak there at all. I will do the bubbles in recovery test first thing in morn .though. Thanks for such a fast response. I thought I was the only caddy owner not bieng able to sleep cause of worry over my baby !
Chucky

[illumina]

Originally Posted by chuckles_100

I dont smell any a/f when im driving or sitting idling and the oil is a perfect golden colour. Still all kinds of power too. Only a/f I seen was when some came out the top of the overflow cap. The hoses where fairly hard but not to the point of bursting. seemed fairly norm actually. I looked all around the w/p and didnt see any leak there at all. I will do the bubbles in recovery test first thing in morn .though. Thanks for such a fast response. I thought I was the only caddy owner not bieng able to sleep cause of worry over my baby !
Chucky

test the pressure of the radiator too. there could be a minute leak somewhere that cannot be easily seen.

if the bubble test proves bubbly, do a compression test. water will not always go into the oil if a gasket goes.

also, pay wttention to the intake manifold: could be an external leak somewhere.

[Stoneage_Caddy]

Radiator cap ? 5 bucks to rule that bad boy out ...sometimes they wont hold pressure

I have to ask ....how long did you wait till you pulled the rad cap on a hot (according to sensor) engine ?

Sorry , knew a guy that burned the hell out himself that did something like that ...you probabaly know beatter but i just have to ask ...no offense dude

[BeelzeBob]

From what you say it was fine after you replaced the cap....???

Those temps look fine. I would just monitor the coolant in the radiator itself for several days when cold. The rad should stay completely full right to the cap when cold. If not, then the cap isn't working correctly. Mark the coolant recovery bottle when cold so you can see that the level is always the same cold.

You put the correct cap on?? The correct cap has a drop valve in the center that allows coolant to be sucked back in when the system cools. The drop valve is a bottle cap shaped piece in the center of the rubber seal that hangs down a little into the radiator neck. Be sure it is the correct one as if someone gives you one for a Northstar it will be the wrong cap.

Did you put the GM coolant supplement in the coolant system as is required for that engine to guard against any internal coolant seepage into the oil.?? The supplement/sealer is mandatory. Go to the search feature in the forum tool bar above, type "coolant supplement" into the drop down box and search. Read my posts on the subject. Put the supplement into the radiator at the radiator cap . It is mandatory that you use it with the 4.9.

Are you sure the coolant is mixed 50/50?? I would check it with a refractometer to be sure. It must be 50/50 (-40 freeze protection) to avoid premature boiling.

Otherwise, the system sounds like it is operating correctly per your description. The cooling fans are supposed to turn on at 225 or so so that is normal to see that temp idling. My guess is that the system was filled a bit fast and had an air pocket in it that purged out when you drove. The air may have vapor locked the water pump for awhile so it wasn't pumping and caused the overheat and low appearing coolant. I think it sounds fine now. But be sure to get the coolant supplement/sealer into the system. It is important with that engine.

If it continues to give you sporadic problems I would replace the water pump. If someone put an aftermarket pump on the engine (they are much less expensive than the OEM pumps) the impeller may be loose on the shaft and slipping and not pumping. This cannot happen with the OEM pump as the impeller is welded (that is one reason it is more $$$) but the pressed aftermarket pumps have been known to shed the impeller causing overheats even though the pulley on the belt was turning fine and the pump was not noisy or leaking.

[CCW]

I have a similar problem. I am brand new to this site and also the brand new owner of an 82 Eldorado with a 4100 engine. It started overheating on me last week with coolant coming back out the overflow. The coolant light and 'stop engine' light also began to come on. I replaced the thermostat and tightened the althernator belt(which was also a little loose causing my fan not to spin and battery not to charge). Now my coolant light doesn't come on but my car still overheats and the 'stop engine' light comes on quicker than before, after about 5 minutes of driving. I do not have any white smoke, I don't smell any coolant, and my oil looks just fine. When I fill my radiator up and let the car sit overnight, the radiator is basically empty the next day. I also notice a small leak coming from underneath the car on the driver's side, but further back than the radiator sits. Could this be caused by my water pump? I took it to a shop and they said my overheating was caused by the radiator, water pump, thermostat, and I needed new belts. I'm new to car repair and wanted to do as much as possible by myself.

[chuckles_100]

Originally Posted by bbob

From what you say it was fine after you replaced the cap....???

Those temps look fine. I would just monitor the coolant in the radiator itself for several days when cold. The rad should stay completely full right to the cap when cold. If not, then the cap isn't working correctly. Mark the coolant recovery bottle when cold so you can see that the level is always the same cold.

You put the correct cap on?? The correct cap has a drop valve in the center that allows coolant to be sucked back in when the system cools. The drop valve is a bottle cap shaped piece in the center of the rubber seal that hangs down a little into the radiator neck. Be sure it is the correct one as if someone gives you one for a Northstar it will be the wrong cap.

Did you put the GM coolant supplement in the coolant system as is required for that engine to guard against any internal coolant seepage into the oil.?? The supplement/sealer is mandatory. Go to the search feature in the forum tool bar above, type "coolant supplement" into the drop down box and search. Read my posts on the subject. Put the supplement into the radiator at the radiator cap . It is mandatory that you use it with the 4.9.

Are you sure the coolant is mixed 50/50?? I would check it with a refractometer to be sure. It must be 50/50 (-40 freeze protection) to avoid premature boiling.

Otherwise, the system sounds like it is operating correctly per your description. The cooling fans are supposed to turn on at 225 or so so that is normal to see that temp idling. My guess is that the system was filled a bit fast and had an air pocket in it that purged out when you drove. The air may have vapor locked the water pump for awhile so it wasn't pumping and caused the overheat and low appearing coolant. I think it sounds fine now. But be sure to get the coolant supplement/sealer into the system. It is important with that engine.

If it continues to give you sporadic problems I would replace the water pump. If someone put an aftermarket pump on the engine (they are much less expensive than the OEM pumps) the impeller may be loose on the shaft and slipping and not pumping. This cannot happen with the OEM pump as the impeller is welded (that is one reason it is more $$$) but the pressed aftermarket pumps have been known to shed the impeller causing overheats even though the pulley on the belt was turning fine and the pump was not noisy or leaking.

Hello BBob
I've read alot of the advise you have given and you sure know ya caddis I read your reply this morning and immediatly went and checkedthe rad cap and yes its just like you described. And Yes I also put in the pellets from GM also. Alot of protection for 5 bucks! I mixed the coolant myself so im fairly certain its correct but I will check to be absolutely sure. If it was an air pocket would it have taken about 700 miles to show up? I've never owned a 4.9 and I am really impressed with the STS package.And on a seperate note be careful if you armour all you leather seats. went to get in car inna hurry and almost slid under dash lol
thanks chucky

[chuckles_100]

Originally Posted by Stoneage_Caddy

Radiator cap ? 5 bucks to rule that bad boy out ...sometimes they wont hold pressure

I have to ask ....how long did you wait till you pulled the rad cap on a hot (according to sensor) engine ?

Sorry , knew a guy that burned the hell out himself that did something like that ...you probabaly know beatter but i just have to ask ...no offense dude

No offense taken dude!! I squeezed hoses and was no pressure as it all was bubbled into resevoir. As a precaution I stood away from cap and covered with rag s l o w l y removed it one click. nothing so I knew wasnt pressureized.In 1992 I had a reading on an '81 regal of 240 and put my hand on cap to see if it was vibration due to overheat and it just blasted of the rad and hit me in the chest. I had 1st and second degree burns from groin to neck. Let me tell ya Im so careful Its scary!!lol
So dont worry about me taking offense on legitamite qeustions. thanks for all your time guys
chucky

[chuckles_100]

:madtalkin well I put the car on a pressure test @ 15 psi seemed ok. drove car about 15 miles was all happy an then PRESTO it overheated all of a sudden and FAST. went to 245 and I shut it off. looked under hood and was spewing a/f out of the top of the resevoir. Limped home shutting car off when ever it started to heat (which was fairly often). I reached 60 mph and temp stayed rocksolid at 199. slowed down and temp started to skyrocket.I had also tested a/f and it was at -40. When motor was cold I removed the small 1" hose beside stat housing and breifly started car and it spat a/f out so I'm assuming that the w/p is operating. I priced a w/p @ the dealers and holy shit!!!! Was $200.00 @ dealer list!!!! I've actually found a motor rebuilder that will rebuild me a new 4.9 for $1900. Gives me 1 year 20000km warrenty and for $200. more I'll get 3 years and a 60000 km warrenty. geuss now ill DEFINATLY not get layed for a l o n g time....
thanks for all your advice dudes
chucky

[illumina]

Originally Posted by chuckles_100

:madtalkin well I put the car on a pressure test @ 15 psi seemed ok. drove car about 15 miles was all happy an then PRESTO it overheated all of a sudden and FAST. went to 245 and I shut it off. looked under hood and was spewing a/f out of the top of the resevoir. Limped home shutting car off when ever it started to heat (which was fairly often). I reached 60 mph and temp stayed rocksolid at 199. slowed down and temp started to skyrocket.I had also tested a/f and it was at -40. When motor was cold I removed the small 1" hose beside stat housing and breifly started car and it spat a/f out so I'm assuming that the w/p is operating. I priced a w/p @ the dealers and holy shit!!!! Was $200.00 @ dealer list!!!! I've actually found a motor rebuilder that will rebuild me a new 4.9 for $1900. Gives me 1 year 20000km warrenty and for $200. more I'll get 3 years and a 60000 km warrenty. geuss now ill DEFINATLY not get layed for a l o n g time....
thanks for all your advice dudes
chucky

before you go and spend $1900.00 on a new engine (highly doubt you need one), spend $5.99 on a new thermostat and see if it helps you out.

[chuckles_100]

Originally Posted by illumina

before you go and spend $1900.00 on a new engine (highly doubt you need one), spend $5.99 on a new thermostat and see if it helps you out.

The t/stat is only a month old but like you said worth 6 bucks to rule out huh?
thanks ill try it first thing in A.M
chucky

[Kev]

Hey, what about testing the thermostat you have? Pull it out, put it on the stove in a pot of water with a candy thermometer and light a fire under it. You should see it open at the proper temp and and close when it cools down. Just because it's new doesn't mean it's working right.
Would be sweet if a good t-stat solves your problem.
Good luck!
(by the way, if it does solve the problem maybe you can find something nice for your honey with the money you saved, might improve your lovin' prospects?)
Go get 'em guy!

[youbetcha77]

A sticking thermostat can do that. I have bought new ones and put them in and had them never open and I have bought new ones and put them in and had them open and never shut again. Its always a possibility.

Blaze