I have an 86 951 which runs great and is my DD. I have been having a very peculiar issue of late. It has been happening every week or so. If the car has been sitting either overnight or in the afternoon after being cold at work, it may happen. I can start the car and drive for as short as 1/2 mile or so. I see what seems to be smoke coming out from under the side of the hood in the vicinity of the overflow. It has a smokey/plastic burning smell but seems to be steam. I usually smell it before I see it. The problem is I usually notice it when sitting jammed in traffic and I can't get off the road to check it. By the time 1-2 minutes goes by and I get off the road, it has stopped. I pop the hood and can no longer smell it and there is no evidence of any overflow or leaking antifreeze even from the overflow tube. The temperature gauge is cold and in the 2 minutes the car has been running the block is still cold. I can't figure out what is causing the smell/smoke. It never happens when I can get to it to hunt it down. I'm not running the heat or air.

A bit of history that may or may not be related: About a month ago I had the front end of car on stands chasing an exhaust leak. I had the car idling (no I wasn't under it) and it burped a bunch of antifreeze out on the ground, from exactly where I have no idea, it wasn't the from overflow. I do suspect that I had some air in the system. I thought maybe a head gasket issue and I checked the oil and coolant and other than the coolant being a little low everything was fine. The car runs great and no different than it has for the year that I have owned it. It started sometime after I replaced every hose in the vacuum system and had the injectors cleaned but That was 2-3 months before this started. Other than that it has been business as usual. I do have an oil leak somewhere at the rear of the engine and thought maybe was some dripping on the exhaust but I don't think the exhaust is even hot enough sometimes when it happens to even burn oil. The thing that concerns me is the smell, as I cant exactly tell what it is.

Any ideas?

 

I'd probably start by pressure testing the cooling system. You can get the Stant or Sears or similar testers. They are easy to use and will reveal just about any external coolant leak. If no coolant leaks, I'd check the exhaust for signs on oil burning on them. Check the cross-over right under the rear main bearing, and the headers. If oil(or ps/brake fluid) is burning on the exhaust, it will show up as ugly carbon/burn stains. Keep close eye on all your fluid levels as well. If something is burning off, eventually it will be low...

 

No need for a pressure test today, I drove to work and right when I pulled in it started. Billowing from both sides of the hood. Of course it was raining but I popped the hood and saw coolant dripping from where the rubber hose from the heater core connects to the hard pipe. I pressed on the hose and it started gushing. It was dripping down on the crossover and burning. Ordered a replacement heater hose kit from LR.

 

Not sure exactly where yours is leaking, but if its at the firewall, take a close look at the pipe stubs sticking out for roundness, etc. I ended up changing mine when I couldn't get things to seal there.

https://rennlist.com/forums/944-turb...-question.html

 

Glad that you found the leak. Be also glad that you have a later car where the heater hoses clamp on the outside of the firewall. Hopefully that will save you lots of grief and gnashing of teeth..

 

It is leaking where it clamps to the hard pipe. It does look like reasonably easy access. We'll see this weekend after my parts show up.

 

Just closing the loop. That was the problem, replaced the heater core to hard pip hose and all is good again!

 

Good for you! Great going!