I took my '95 Z out for a ride today...don't take it out much in the winter but the roads were clear and no snow. Soon as I got back in the driveway, it started running rough, almost backfiring but more like softer "pops" from the exhaust, and I started getting thick white smoke from both tailpipes. The exhaust does smell of anti-freeze somewhat. Also, there was a small amount of what looked to be condensation on the bottom of the oil cap..a drop or two. Just need to get set off in the right direction I guess...head gasket the only thing that could cause those symptoms? If so..fixing this will certainly test my abilities..I bought this car to have something to have fun with, work on etc. No garage so If I do it myself it'll be a driveway job when the weather is cooperating/when I can. Million dollar question - how much on average does it cost to have a shop do a head gasket repair? I suppose when I find that out I'll be doing it myself but just need a point of reference. If this is a blown head gasket...does the antifreeze mixing with the oil damage the engine in any way?

A little background...last fall the water pump went and I replaced it myself. It's the only other major thing that's gone wrong with it. The only issue I had after that replacement is that I had very little heat compared to what it was prior. I bled and bled the coolant system but I never did improve the heat. Never overheated, even stopped in traffic. Until winter...last week I had it out and while waiting in line at the carwash, temp started to climb. Never got in the red, but it did get higher than it ever has before. Revved the engine and the temps dropped almost immediately. Have never had the temp climb past normal while driving, only while idling in cold weather.

Any suggestions or insight would be welcome. I did search the threads in here on head gasket issues and saw that the haynes manual is recommended..is there a step-by-step for it in there..or is it more of just an aid in getting everything back together without ending up with a pocketful of extra bolts? Be nice if someone had a step by step (shoebox style) on it.

I put my actual questions in bold. Sorry if this post is long but it's been my experience that more info is much better than not enough.

And please, I'm looking for useful information here. Do not post in this thread if it's going to cause conflict or be non-helpful..I'm bummed enough as it is.

Thanks in advance...

 

sounds like a blown head gasket if your exhaust smells sweet like antifreeze. changing the gaskets isn't too incredibly challenging if your mechanically inclined at all. I don't know what a shop would charge but I am willing to bet it's way way too much. You'll need a top end gasket set and I would use new head bolts. Your also going to need to take the heads to a machine shop and have them checked out and most likely planed flat again.

 

You should first check to see if, in fact you have a head gasket problem. Borrow a pressure tester from a shop like AutoZone to pressurize the cooling system to see if pressure holds.

Then, if pressure doesn't hold and based on the other symptoms, you have a head gasket problem.

I agree with LearJet, it's not all that difficult to do and will be a LOT cheaper than having a shop do it since the major cost is in the labor. if you decide to have a crack at it, we can walk you through what needs to be done.

Oh, and YES. Coolant in the oil will kill the bearings and the damage the crank journals too.

Jake

 

Heater problems in 4th gens are common. A few factors contribute to this. One is the restrictor on one of the heater lines cutting back flow to the heater core. The fact that this is the only SBC to have the flow of coolant reversed isn't a help. The build up of crap on the engine's coolant passage walls sloughing off and flowing into the rather long tubes leading up to the heater core also. Only way to fix the problem is a complete and thorough coolant flush and getting fresh water to flow freely through the heater core. I had to blow mine out with compressed air before it would flow. Don't forget to either refill with pre mixed 50/50 or use only distilled water to cut pure coolant/antifreeze.

As far as the possible head gasket. A coolant pressure test might not show the problem. I will tell you this. It is very hard to get some of those to seal good while your pressurizing the system. This leads many to believe they have a leak when they don't actually.

Last thing that usually gives good results is a leak down test. Don't forget the plugs will give an indication of a cylinder burning coolant.

FYI you know how to make anti freeze?


Hide her underwear. LOL

 

I'm fairly sure at this point it's the head gasket. After sitting all night, I checked the oil cap this morning and it did indeed have condensation on the bottom of the cap...much more than yesterday. Coolant is low but none of it is under the car. This blows, I just spent 3k on this car in august.

It will be weeks before it is warm enough to do this sort of work to it..would it be bad for it to sit this way with antifreeze in the oil if it's not run? Should I drain the oil and replace it?

I'm also wondering if it's worth all this time and effort if it's possible that damage has been done to the crank/bearings. I'd hate to do all this only to find out there is something wrong there...

 

It's always POSSIBLE for another thing to be cause, other than a leaking head gaskets. That's why it's best to test first, repair as needed second.

Here's the procedure to help identify the area of the leak, taken from the 96 Vette Factory Service Manual; page 6-165:

1. After the system (cooling) has cooled, removed the radiator/surge tank pressure cap.

2. Connect the cooling system tester to the radiator/surge tank.

3. Apply normal system operating pressure. Do not exceed 136 kPa (20 psi).

4. Watch the gauge needle for an indication of a leak. Examine all cooling system connections and components, including the radiator and the heater core, for leaking coolant.

5. Tighten the hose connections or repair as required.

6. Check the radiator/surge cap with the "tester" in order to ensure the cap maintains the correct pressure. (Attach the tester directly to the cap and pressurize to 20 psi)

7. If the radiator leaks during the pressure test, mark the area so the leak can be located once the radiator has been removed from the vehicle.

The FSM shows a part number of the tester but most guys/stores don't have access to that specific one. Instead that use the one from AutoZone/O'Reilly's/Advance Auto, etc., which does the same job, just has a different part number.

This is the test I'd do FIRST, since it's so simple to do and has no real associated cost.

Hope this helps.

Jake

 

I know this is a very general question...but since I have to pull the heads off anyway...what mods should I do? I guess I'm trying to turn a crappy situation into a good (fast) one, lol. And remember, this car is stock.

I wouldn't want to spend more than 1.5k total...and I'm not looking for massive hp, 400+ would more than satisfy me. The car is completely stock right now...and it's a good lookin car, I replaced quite a bit of the interior as well, so I'm keeping it. I was thinking a cam obviously but not sure which one because I really need suggestions there. I'm not up on cams and heads and what not but I'm trying to come up to speed . I would need a streetable setup, something with a little attitude but I don't need a racecar. When I pull these heads off I'm going to have them checked...if they're good I can either put them back on, port them out or sell them and get aftermarket heads...just don't know yet. Due to cost I'll most likely just stay with the stock heads if I can and they're still ok. Guess I'm just looking for what some of you would do in my situation, if you have to pull the heads off anyway......

Jakejr - thanks for your suggestions, you've been real helpful. Sometime next week I'll pressure test the coolant system and go from there but smelling anti-freeze in the exhaust, I'm pretty sure I have a bad head gasket or head (hopefully not).