GnatGoSplat Posted October 5, 2011 Report Share Posted October 5, 2011 The 94 convertible seems to have sprung a mysterious coolant leak while it's been sitting, waiting for a new starter. It's dripping coolant off of the front edge of the transaxle oil pan, behind the engine oil drain plug. It doesn't have to be running, it's a constant drip drip drip like a leaky faucet just sitting there cold, not having been driven for a week. Any guesses where it could be coming from? I can't get a visual on the source of the leak from the top side of the engine. I'm really worried it could be an external head gasket leak. Quote Link to comment Share on other sites More sharing options...
GOT2B GM Posted October 5, 2011 Report Share Posted October 5, 2011 A few possibilities that arent quite as serious: the LIM to plenum coolant port o-ring the front coolant bypass pipe to plenum connection (the 3" piece of 3/4 hose below the TB) The coolant quick connector going into the LIM Quote Link to comment Share on other sites More sharing options...
GnatGoSplat Posted October 5, 2011 Author Report Share Posted October 5, 2011 I can't visualize where the LIM to plenum coolant port O-ring is. I've changed out the LIM before, but not really remembering any O-rings. Where's the best spot to see it? I think the hoses below the TB were dry, but hard to tell because it's oily there from the oil pump drive O-ring leak. I'll have to double-check. It was dry at the coolant quick connector. Quote Link to comment Share on other sites More sharing options...
GOT2B GM Posted October 5, 2011 Report Share Posted October 5, 2011 The plenum seals onto top of the LIM right beside where that 3" hose connects. There is a port there sealed only by an oring. Part of the TB heater circuit. Quote Link to comment Share on other sites More sharing options...
GnatGoSplat Posted October 5, 2011 Author Report Share Posted October 5, 2011 Thanks, I'll be sure to check it out. It's definitely greasy looking in the valley from the oil pump drive, but I didn't see anything resembling coolant anywhere in the valley area, but it's worth double, triple, quadruple checking. This may be the end of the road for the vert if it's the head gasket as that's a bigger job than I want to tackle. Quote Link to comment Share on other sites More sharing options...
GOT2B GM Posted October 5, 2011 Report Share Posted October 5, 2011 If its a HG, sell it to Nunzi, he needs a vert, he just doesn't know it yet. Quote Link to comment Share on other sites More sharing options...
GnatGoSplat Posted October 6, 2011 Author Report Share Posted October 6, 2011 LIM to plenum under the TB, dry. T-stat housing, dry. Heater pipe quick disconnect, dry. All dry up there. Time for panic? Or any other ideas? I guess it's not really worse. The dripping is significantly less now that my wife is driving it again. I think it started dripping because it'd been pooling up on top of the transaxle housing for a week while waiting for a new starter. Quote Link to comment Share on other sites More sharing options...
GEN1Z34 Posted October 6, 2011 Report Share Posted October 6, 2011 Try checking heater core connects and lines for cracks/leaks.. Also maybe check the LM gaskets, specificly where the cylinder head coolant port is near the T-stat housing.. Here: Quote Link to comment Share on other sites More sharing options...
GnatGoSplat Posted October 6, 2011 Author Report Share Posted October 6, 2011 Thanks, I'll take a look when I get home, but I didn't remember seeing anything that looks like coolant in the whole valley area. That is one nice looking 3.4 DOHC! Quote Link to comment Share on other sites More sharing options...
GEN1Z34 Posted October 6, 2011 Report Share Posted October 6, 2011 Thanks, I'll take a look when I get home, but I didn't remember seeing anything that looks like coolant in the whole valley area. That is one nice looking 3.4 DOHC! Thanks! The thing is, there's a step in the block casting in that area.. Could be that the leak is dripping below the step and running down the back side of the block. If you suspect a head gasket issue you could try a compression test.. But being the bank against the firewall you know how fun that would be..lol Quote Link to comment Share on other sites More sharing options...
GEN1Z34 Posted October 6, 2011 Report Share Posted October 6, 2011 (edited) Oh yeah, could also be the freeze plug in the head there, but I think you'd see that fairly easily.. But definetly check the heater core lines.. Especially where the hard coolant line runs along the passenger fender well.. It makes a turn back in there where you can't see.. A couple of years ago I had a coolant leak down while my 92 z34 was parked too.. Pulled the fender well and uncliped the line from the chassy and it just crumbled in my hands.. Edited October 6, 2011 by GEN1Z34 Quote Link to comment Share on other sites More sharing options...
GnatGoSplat Posted October 7, 2011 Author Report Share Posted October 7, 2011 Thanks, I could be wrong, but I don't think a compression test would find a head gasket crack that runs from cooling passage to the outside. I think it would only show up if the crack runs into the combustion chamber. I'll be sure to check the other stuff when I get motivated to get under the car. Quote Link to comment Share on other sites More sharing options...
GOT2B GM Posted October 7, 2011 Report Share Posted October 7, 2011 If you have the cooling system pressure tested the external leak will show. Quote Link to comment Share on other sites More sharing options...
GEN1Z34 Posted October 7, 2011 Report Share Posted October 7, 2011 If you have the cooling system pressure tested the external leak will show. This, is what I should have said...my bad.. Quote Link to comment Share on other sites More sharing options...
GnatGoSplat Posted October 7, 2011 Author Report Share Posted October 7, 2011 Think this would work? http://cgi.ebay.com/ebaymotors/Mityvac-MV4560-Cooling-System-Pressure-Test-Kit-/140497358365?pt=Motors_Car_Truck_Parts_Accessories&hash=item20b64b8e1d Like everything else, if I have to pay someone else to do it, I'll procrastinate and it'll never get done so any DIY solution is preferable. I may procrastinate on this anyway, it seems the leak isn't as bad as I initially thought. It had just been pooling for a week so it was around a week's worth spilling off the tranny all once. Quote Link to comment Share on other sites More sharing options...
GEN1Z34 Posted October 7, 2011 Report Share Posted October 7, 2011 I can't see why it would'nt.. I have used the Mity vac for brakes before.. I think you'll be okay with that.. Yup, mine leaked too.. A year and a half later I desided to dig into it.. Just keep an eye on your coolant level till you deside to bust knuckles.. Quote Link to comment Share on other sites More sharing options...
GnatGoSplat Posted October 8, 2011 Author Report Share Posted October 8, 2011 Your head gasket had an external coolant leak? It was the first thing I suspected when nothing up top appeared to be leaking because it happened to my 89 and usually what happens to one W-body often happens to others too! Quote Link to comment Share on other sites More sharing options...
GEN1Z34 Posted October 9, 2011 Report Share Posted October 9, 2011 (edited) Your head gasket had an external coolant leak? It was the first thing I suspected when nothing up top appeared to be leaking because it happened to my 89 and usually what happens to one W-body often happens to others too! No, no, It turned out to be that stupid hard line that later crumbled.. But it leaked for a while and I just kept an eye on my coolant level till I tore into it.. I honestly have'nt seen LQ1's pop head gaskets tho I know it can happen of course. I have the old set from another LQ1 I am working on and they (aside from being used) are in excellent shape.. I wont reuse them but, they came off looking very good for being nearly 20 years old and 130k+ on them.. Basicly I am willing to go out on a limb here and say it's likely something other than a head gasket.. There are so many coolant lines/connections running around under our hoods that I bet it's one of them or a heater core/line issue.. Remember coolant is under pressure especially when you're driving, it can come from one place and squirt clear to another, pool up and drip later.. Edited October 9, 2011 by GEN1Z34 Quote Link to comment Share on other sites More sharing options...
berettagtz Posted October 15, 2011 Report Share Posted October 15, 2011 Its likely your lower intake gasket, had that exact thing happen to me on a 92 lumina Z34 Quote Link to comment Share on other sites More sharing options...
GnatGoSplat Posted January 23, 2012 Author Report Share Posted January 23, 2012 Yep, I think you guys who suspected the LIM are right. It's gotten worse, and now there is visibly green coolant pooling up in the valley along with the oil that was already there from the oil pump drive. I need to change it soon, because it's now leaking about a quart a week. I guess they only last about 9-years, the Fel-Pro replacement I put in it only lasted as long as the OEM did. Think it would be better to use RTV, or should I just install it dry as GM recommends? I don't remember what I did last time, probably installed it dry. Gotta think up some clever way to seal the oil pump drive leak again as well. Might as well do it with the LIM off of it. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.