Leaky manifold gasket

[JimMadsen]

1998 Chevy Lumina 3.1 with possible thermostat issues. Past 2 days temp climbed to around 240 before opening on my 17 mile commute each way to and from work. Once it opened, had heat and no issues for rest of ride. This morning, redlined on temp before opening and dropping down to cold. Rose back up to around 180 before dropping to cold. Repeated several times. After about 15 miles of the commute, finally started to have consistent temp gauge readings and heat. My train of thought is this is a reaction to t-stat opening and closing. Either that or low coolant for some reason.

 

Brought to a shop around corner from my work:

 

Shop said leaky intake manifold gasket. He said appears to be leaking outside the engine along driver side, coolant itself does not appear sludgy or anything. When I pick up the car at lunch, I will try and get him to show me where.

 

 

He said should replace upper, lower and phelum (sp?) gasket and replace egr valve? I have the service manuals at home and can park this thing most days of the week. I am a good with doing fixes myself as long as I have the resources to learn as I go. Just concerned about how long I can limp this along with adding dex cool as needed. OR (and I will mention the forbidden) can I add some stop leak? Had a drain and fill a few months back, they may not have added any of the tabs that are called for in the service book.

 

 

Thoughts? Wanted 750 for the job and 2 days work. I am willing to do this myself, just wish it was not December and snowing.

[Galaxie500XL]

Jim, I'm a little confused. Is this overheating occurring while driving say, on the highway going 40-50 or better, or while in stop and go traffic? I've seen cooling fans that still moved, just not enough that would cause those kind of rises in stop and go, but once sufficient airflow was established by going say 40 or better, the temps would drop and stay there as long as you maintained that speed.

 

Low coolant would certainly cause issues, but generally, if it's THAT low, it's not going to correct itself as you continue down the road...but saying that, a sticky thermostat certainly sounds plausible.

 

Did you notice the coolant being low before taking it to the shop?

[JimMadsen]

This occured on a highway with some rush hour traffic. The heat would come and go with the temp needle, needle rises the heat got cold, needle falls (signifying the tstat opened) and heat came back. After merging onto another highway, no speed change or change in driving conditions, operated normally for last 2 miles of my commute.

 

Once care cooled some, went outside to look and saw res was low to the point the drain was barely covered. Opened the rad cap and did not see any dex cool. I did see the top of the internal workings of the rad.

 

My coolant overflow was in proper range when I did an oil change about a month ago. The shop said they added more, I verified that they added dex cool and not green coolant. Guy said interchangable until I told him green and orange make mud. He said thats from oil (sure, but not just oil!). I made that mistake which led to my drain and fill those few months ago. Gaskets pressure tested then and were fine. I am going to get him to show me where leaking and I will try and get a picture posted when I pick the car up. He said the coolant level was really not that low. Heck they ain't charging me for topping it off so they must not have put much in.

[RobertISaar]

The heat would come and go with the temp needle, needle rises the heat got cold, needle falls (signifying the tstat opened) and heat came back.

 

this shouldn't happen. coolant is pumped through the heater core at all times, regardless of the thermostat being opened or closed.

[JimMadsen]

Picked the car up. Mechanic showed me some pooling coolant under the egr valve. He claims need to change upper and lower manifold gaskets and the piping for the egr. He further went on to say that this has been ongoing for a while as evidence of gunk build up on walls of my overflow. I explained that I had a drain and fill where the tank was scrubbed back in Aug after mixing dex and green. His claim is they are ok to mix. Yeah, been there, done that. No thank you. His belief is that I have been leaking for awhile but was unable to explain why dexcool was clear after 4 months of a "leak". He claims garage I brought it to may not have known how to check manifold pressures. I hate it when garages have peeing contests.

 

All that being said, I am going to re-torque all the bolts on the engine cover to tighten things down a bit and keep an eye on the coolant level. This should get me through to some warmer weather where I will do a proper job and replace the gaskets.

 

RobertlSaar: one of the things I love about forums like this is when I am wrong on something, I can easily be corrected and get the right information for the future. Do you think low coolant alone would cause this? If you think the tstat should be fine, I may not worry about replacing it when the engine is open when I fix the LIMG. - thanks

[RobertISaar]

low coolant.... maybe? there are a lot of weird things happening. coolant level NEEDS to be correct at all times though, otherwise it can cause some phantom issues, especially if air pockets were to form somewhere in the engine, that will cause a whole range of headache.

 

i would replace the thermostat regardless.... they cost ~$5 and do wear out. sticking can go from okay(mine does to ~208 or so) to worse pretty quickly.

[JimMadsen]

low coolant.... maybe? there are a lot of weird things happening. coolant level NEEDS to be correct at all times though, otherwise it can cause some phantom issues, especially if air pockets were to form somewhere in the engine, that will cause a whole range of headache.

 

i would replace the thermostat regardless.... they cost ~$5 and do wear out. sticking can go from okay(mine does to ~208 or so) to worse pretty quickly.

 

Yeah, I agree with you 100% on all of this. Weather is supposed to be pretty good this weekend. I will look at swapping out the tstat then. As for the other issue with the LIMG, I am going to tighten everything down and watch levels every other day until I can devote the time to it. But by changing tstat first, I can help narrow down the phantom problem. First, I will see how it acts going home this evening. If it was low coolant, then the top off I got from the shop should solve the problem until the level gets low again.

 

Air pockets might very well explain what I saw, but like you said... maybe.

[JimMadsen]

This looks like everything I should need when doing a gasket replacement. I do not see any reason not to replace everything.........

 

http://www.amazon.com/Fel-Pro-MS98004T-Intake-Set-3-1/dp/B000CSC5MG/ref=au_pf_ss_1?ie=UTF8&Make=Chevrolet|47&Model=Lumina|465&Year=1998|1998&carId=002&n=15684181&s=automotive

[Heartbeat1991]

Sounds more like an air pocket to me. If the heat is going cold midway through your drive, that cannot be from the coolant suddenly going cold. A sticky t-stat could be a culprit too. if it boiled over a little when getting to the 240-redline, you'd have lost some coolant and could have some air in there. I would do a t-stat and refill with dex-cool and burp out the air, then just keep an eye out for it.

 

Note : regular green and dex-cool don't mix, as you know. The garage that told you they mix is wrong. There is a more yellow-ish color that supposedly will mix, but I just use orange. It's safer that way. Either buy 50/50 mix or use distilled or deionized water with dex-cool. Tap water defeats the purpose of using the dex to begin with.

[JimMadsen]

Sounds more like an air pocket to me. If the heat is going cold midway through your drive, that cannot be from the coolant suddenly going cold. A sticky t-stat could be a culprit too. if it boiled over a little when getting to the 240-redline, you'd have lost some coolant and could have some air in there. I would do a t-stat and refill with dex-cool and burp out the air, then just keep an eye out for it.

Gonna do that this weekend. Or at least give it a good ole college try! Unless the topped off dex cool fixes the problem and the tstat appears to be working "normally"

 

Note : regular green and dex-cool don't mix, as you know. The garage that told you they mix is wrong. There is a more yellow-ish color that supposedly will mix, but I just use orange. It's safer that way. Either buy 50/50 mix or use distilled or deionized water with dex-cool. Tap water defeats the purpose of using the dex to begin with.

 

Wife is at walmart now picking up some prestone 50-50 dex-cool compatible stuff. Funny thing is the guy told me to mix some in a glass and see what happens, I may still do that and bring it in for him!

Edited December 17, 2013 by JimMadsen

[Heartbeat1991]

It won't do much in a glass. They will mix. The problem is that the green coolant corrodes the aluminum and when all of that mess starts to mix, it forms a nasty, muddy sludge.

Edited December 17, 2013 by Heartbeat1991

[Galaxie500XL]

At the risk of thread jacking, when did GM switch to Dexcool? I've been using the green stuff in the Cutlass since the day I bought it without issue...but I do flush on a regular basis, about every 2 years.

[RobertISaar]

At the risk of thread jacking, when did GM switch to Dexcool? I've been using the green stuff in the Cutlass since the day I bought it without issue...but I do flush on a regular basis, about every 2 years.

 

mid-95, from what i can tell.

 

a neat thing to look for is if the lettering on your coolant resivoir is green or orange, from what i can tell, that is a reliable indicator of what it came with from the factory, if it has never been swapped.

[Heartbeat1991]

At the risk of thread jacking, when did GM switch to Dexcool? I've been using the green stuff in the Cutlass since the day I bought it without issue...but I do flush on a regular basis, about every 2 years.

 

As long as you change it regularly and you don't mix them together, it won't make any difference. Green coolants are slightly more corrosive. And they don't last as long. Dex-cool should last the lifetime of the car without being changed at all. It is the organic based additives present in most green coolant that will gum up in dex-cool. It has been thought that the dex-cool additives are what kills the nylon gaskets as well.

 

1996 was the year most GM engines got the Dex-Cool treatment.

 

You can use green as long as the orange is all flushed out. But the green has a shorter life and is supposedly more corrosive, especially if not changed regularly. I just use the dex-cool. I don't change it unless it's leaked out or I'm doing engine work and it needs to be drained. Even then I usually just dump it back in. LOL

[JimMadsen]

Mine has a dexcool sticker on the frame by the rad cap.

 

Drive home on a snow storm took me 2.5 hours to go 17 miles. This is drive time, not including a 45 minute stop for a doc appointment.

 

Checked the rad to see if there still coolant in there, there was about 3 inches below cap. i do not know where guy filled it to. I started the car and cleared off the snow. Temp gauge did not move.

 

drove about a mile and gauge started to climb. Took me 20 minutes to drive that mile. The gauge started to climb and redlined, stayed there for what felt like a long time but in reality was just long enough for me to pass the exit lane and not have an option to get off highway. the temp gauge dropped right before where the warning light came on. Needle fell to just a tad above 100. Only cold air coming from defrost and vents. Car then warmed up from there to around 160 and stayed there plus or minus 15 degrees. Good heat from defrost and vents.

 

drove the next 1.5hrs without real difficulty. Spent 45 min at appointment and came out to a still warm enough car to blow heat when started. Drove home without issue.

 

i am smelling coolant and did notice it before going to the shop, never could pinpoint it overflow was fine. But now I know where it is leaking from. I do not see more

than a few drops of coolant where I park.

[JimMadsen]

Oh and my wife did not get the 50/50, what do I need to do to make this safe to add into the car? It is dexcool and the car is planned to be parked for a few days til this is figured put. Maybe I will put on ramps with rad cap off to let any air work out.

[Heartbeat1991]

If you're parking it, don't bother to put any into it. Distilled water is recommended to avoid mineral and impurities in tap water that could either corrode aluminum or leave a scale build up.