Topic: coolant leak aound manifold
in Forum: C3 Cooling and Heating Systems
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Hi, my 78 has developed a mystery coolant leak. I originally thought either the thermostat housing was leaking or one of the hoses around it. I could see coolant building up in the hollow parts of the inlet manifold near the thermostat - but it appears that the coolant is actually coming through from the manifold. Could this be a gasket problem - and if so is that a major? Apologies but my mechanical skills are pretty poor and I have much to learn.
For those that are interest I bought my corvette in Kansas City a couple of yeaars ago and drove her through to LA via Route 66 (partly) and then shipped her home to New Zealand where she now proudly resides!
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I have a 79 and had the same problem, but mine turned out to be the thermostat housing. Gasket was replaced twice before we replaced the housing. Even though the housing didn't appear to have an issue, it would allow a small amount of coolant to leak out and would puddle in the intake. I cant see how coolant would EVER be able to go through the manifold (without it being cracked). Hope this helps!
|UPDATED|7/13/2013 7:49:07 AM (AZT)|/UPDATED|
Barry
|UPDATED|7/13/2013 7:49:07 AM (AZT)|/UPDATED|
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Duncanville, TX - USA
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Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/
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Member: NCRS, NCRS Texas, Corvette Legends of Texas
Could be leaking from around the front intake bolts...that would mean the gasket(s) has failed, or the bolts are not tight enough. You might try tightening the intake bolts, and see if they are loose.
It could also be a cracked intake....
Joel Adams
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Thanks for the advice. I've had a closer look and it's not coming from the thermostat housing or gasket. It looks like the coolant is seeping out through the intake gasket right at the very front adjacent to the rocker cover. Looks like I will have to replace it. Any tips? (Ive read one or two on previous discussions). Is this something a novice with a bit of enthusiasm aand some good mates can attempt? I'm not that keen to pay a workshop to do it!
Lifetime MemberAsh Fork, AZ - USA
Joined: 4/18/2007
Posts: 1058
Vette(s): 1981 Red Interior White exterior
I'll throw my 2 cents in here.
There is a ton of info and folks willing to give good advice on this site and others. Great videos can be found on the web that can help you through most anything you want to accomplish. I'm 50 and started goofing around with cars not for the fun of it but because I never had the money as a kid, so I learned mostly by doing and asking a ton of questions. Still not afraid to ask when I don't know. I've restored a few cars over the years primarily for fun and know my limitations but I'm not afraid to tackle new and mysterious projects because in the back of my head I always know there are pros out there that can fix the stuff I get wrong.
That being said, as long as you can handle not having your car for the length the job will take, add lots of time for mistakes and added problems, I say go for it. Some advice LABEL EVERYTHING!!! Even if this job doesn't need it, it's a great habit to get into.
One other thing about this problem. If you're having coolant leaking from under the rocker/valve cover, you have more of a problem than you might think. There shouldn't be any coolant under the cover. I'm more inclined to think you have a micro crack in the intake.
Dave C..........My mantra: I can not be bought!! Long and short term leases available.
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Yeah, I know, Shut up Dave.
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Frederick, MD - USA
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Vette(s): 1969 convertible L71 427/435 4-speed black interior
When you're done...change the oil and filter. There's a chance coolant could have gotten into the crankcase after doing that job. Ethylene glycol and engine bearings do not mix well at all.
I had the same problem with my 74. I would have a small puddle in the valleys near the upper hose after driving. I did a pressure check and found a tiny pinhole leak as well as slightly loose clamp on the upper hose. Fixed them and no more problem. Good luck on finding yours, I know how it can drive you nuts sometimes.
Larry
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Lifetime MemberTemple City, CA - USA
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Vette(s): 1969 Daytona Yellow. 350 / Automatic.
My dad had a '61 Lincoln Continental. It had a water leak somewhere in the engine. When we couldn't ignore it any longer, we started pulling off all the hoses and wires that covered the engine compartment. Finally we pulled off the intake manifold and set it on the workbench. We couldn't find any leaks on top of the engine. I was staring out into space thinking, when I happened to notice a very small beam of light coming out of the manifold. We looked and there it was, a pin hole had rusted in the freeze plug (casting plug). Fifteen cents later, we had replaced all of the plugs in the manifold and started on the wonderful chore of reassembling that engine. He took it to work the next day.
Man, I loved that car! He traded it in for $800 on a Buick Skylark in 1967. Some kind of California special. Wish I had had $800.
Man, I loved that car! He traded it in for $800 on a Buick Skylark in 1967. Some kind of California special. Wish I had had $800.
in Forum: C3 Cooling and Heating Systems
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