Hello All,

I have a 1985 Z28 with 305 TPI. All stock pretty much but I have this NASTY coolant leak. I checked all the hoses, pipes, clamps, and everything I could look at under and inside the engine bay and followed the heater lines. I have no idea where its coming from!
My best guess is that the heater core or the heater control valve. I hear boiling/hissing sound by the back passanger side of the engine near the firewall. It would appear that the coolant is leaking down the transmission case and running/dripping off of the transmission oil pan and that general area before that on the passengar side. This leak is bad enough that I wouldn't risk driving it to a garage to have a trained mechanic look at it. I can fix what ever is wrong but I'm not that savy as to know the exact problem is. Also it keeps leaking until either the pressure subsides and wherever it is coming from has either leaked out or the level gets below a certain point as far as I can see.

I just started working on this car and it has been running fine until I took the AC pump off and disconnected the hoses as the previous owner broke the pipe leading to the radiator. I didn't drive it around after I did this as my main vechicle is working fine and I was just going to take it out for a spin and noticed a puddle of coolant as I was letting it warm up a bit. I figured I would try asking here before spending an entire weekend riping the dash and what not out to get to the heater core finding that it's not the issue.

Any ideas??? Pleast let me know what you think.

Thanks!

 

Is it leaking onto the transmission from the firewall or the engine? The fact that there is even coolant on the transmission and there is nothing wrong with the hoses makes me think head gasket.

Did you take the a/c compressor out? or did you mess with the blower motor?

 

I do not suspect that it is the head gasket since there is no white smoke in the exhaust and the exhaust dosen't smell any different then normal.

I just took the compresser out and the two hoses connected to it. I did not mess with the blower at all.

It appears to be coming from either behind the engine or somewhere on the fire wall. The coolant is running down the transmission bell housing and off the passengar side. I didn't have the time to put it on a lift, just jacked it up to see if I could see what was going on.


Thanks for the quick response.

 

You need to get a mechanics mirror and look back there and find out what is going on.

 

Freeze plug?

 

I had something very similar happen. I noted that I had coolant dripping down the hard transmission lines. The coolant appeared to be coming from the rear of the engine. I checked everything I cold think of and it ended up being a clamp that was not tight enough on the heater hose going into the firewall. I too had a puddle under the car .

 

My guess would be 1 of the 2 heater hoses going to the heater core. Either a clamp isnt tight or 1 of the 2 hoses has a split in it. I would say its the ? looking hose since it kinda hard to see behind the pass. side head. The other hose is straight and easily seen. Worst case would be the metal pipe that goes to the ? looking hose. Could be rusted thru or cracked.

 

Hello,

Let start with the responses.

(Dakota W.)I do not suspect that is is the frost plug. I had it running earlier this summer. I did not drive it around but jumped it and changed the oil, fresh gas, let it idle, and maybe took it around the block, that sort of thing. It wouldn't make sense that it would go out now. I will take a look over it, it wouldn't hurt to. Happen to know where it is? I can always look at the manual. I thought that they would be on the side of the block and easily spotable but I haven't really gotten to deep into the car quite yet.

THETANK, jermdm : I had already gave the hoses and clamps a good looking over. I took them off and even removed that hard metal line from the body. I didn't disconnect them from the raditor though so I might do that. I was thinking about clamping one end around a dowel and the other around a garden hose, if it fits, and pressure testing the line that way since I don't have a fancy kit and that would be the easiest and cheapest way to test the line for leaks, and start eliminating sources of problems... Since the house line doesn't have too much pressure and I have a flow adjustment end I could monitor it so it doesn't damage the hoses if they are fine. If I decide to do this I will let you know how it goes and you can pass it along. I would only recomend it for coolant lines since they pretty much have water flowing through them anyway, if it works.

Sorry I havn't responded as often as I would like. I work wierd hours but have the weekend off to set aside for projects, away from family and what not. I haven't gotten too deep into this car yet even though I've had it for almost 2 years (pretty much since I joined). Haven't had much time but I am super excited to get into this and with the support from the site to help make this an awesome car , makes it even more enjoyable.

 

You need to get a radiator pressure tester and pressurize your system. That is the easiest and safest way to find the leak.

 

Well what the heck is going on with this project?

 

Take the two hoses going to the heater core and block them off from the rad or heater valve and go from there.

 

I had the same problem on my 87 IROC. It was a leaking intake manifold gasket. You're lucky it's leaking down the back of the engine like mine was. It could be going the other way. Not fun.

 

should be 3 on each side of the block and a larger one on the back in the center of the block.

 

Hello All,

I been dong some work on it these past few weekends and ended up replacing all the hoses and clamps that lead to/from the heather core. Still leaked Got underneath the car didn't see any frost plugs blown out or anything out of the ordinary. I did some more looking around online and it would appear that Hdis2002 might have something there. I plan on replacing the manifold gasket this weekend and feel like that might end these problems! I will let you all know what I figure out after this weekend is over.

Thanks again for all the help.