another coolant loss problem...HELP!

[kaltenacht]

I have a 91 xlt with automatic tranny. A month ago I had an overheating problem. It turned out to be a cracked endcap on my radiator. So a went ahead and bought a new radiator and installed it. Also I went ahead and changed the thermostat both heater hoses and both radiator hoses. Shortly after I noticed an unusal amount of coolant loss. Checked all of my lines and found no leaks of any sort. Also checked heater core and water pump for leaks. Found nothing. Did a system pressure test and I found that I loose a pound of pressure every 30 min. When running and normal driving I loose about a gallon a week of coolant. I thought at first maybe a blown head gasket but I do not have any coolant in oil or no grey/blue smoke in exhaust nor does it smell sweet. So what else could it be? I'm apologize if I posted this in the wrong section but it is kinda hard to find stuff on here when I'm looking on the site with a sidekick2. Any help would be great!

 

[LXNavajo_94]

More than likely your culprit is the infamous lower intake gasket. Mine was leaking down the front passengers side and led me to believe the water pump or hose was bad. It might just be you need to re torque em I can't remember the torque spec but I'm sure some one will know on here. also if re torque doesn't fix it then its time to replace em not a super hard job but not the easiest either do a search on here I did mine using a thread posted here

 

[ActionJackson]

torque spec is 4 to 8 nm I dont know what that translates into inch pounds sorry I dont know the conversion. but im sure someone does

 

[kaltenacht]

Thanks for the helpful replies. I was thinking that the intake manifold gasket could be a possibility but I'm unsure how to test that. Is there any way to test the intake manifold gasket, so that I can be sure it is that before I tear the top part of my engine off? Thanks again.

 

[Rhett]

You should be able to get your coolant system pressure tested for a low price. Might be worth it to nail down exactly where your leak is. They should be able to tell you if it's the gasket or rad, and so forth, and then you can decide if you want to tear it down yourself or no.

 

[mikeinri]

What do you guys consider a good price to have a real pressure test done by a shop that knows what they're doing and can actually find a manifold vs. head gasket leak?

I have a pressure tester, but I'm afraid of doing more damage by using it than living with the small leak I seem to have...

Mike

 

[kaltenacht]

Any more info?

Just an update. I pulled my number 5 spark plug to check the condition of it to see if I may have some oil or coolant seepage. The plug came out very clean with only a little white chalky buildup on the side electrode. I am still loosing coolant at the same rate. I was wondering if anyone can point me in the direction of another thread that describes the symptoms of a blown lower intake manifold gasket? Or just describe it to me? Also, I know there is a thread on here someplace that talks about the steps in replacing the gasket. If anyone could point to that thread I would be appreciated. Any information would be great because I want to be sure that it is the lower intake manifold gasket BEFORE I purchase the necessary gaskets and tear my engine apart, only to find that it is something else. Thanks again for the previous help and I look forward to any responses.

 

[LXNavajo_94]

One of the biggest symptoms of a bad lower intake manifold gasket is a pinging under load, or going uphill. You will know if its doing it by the rattling sound. Kinda like someone shaking a can of spray paint. Other than that I don't know of any one specific test for it .

 

[Creager]

If its not on a the ground, then there are a few places that coolent may be going

1) Its getting burned: sucked in the combustion chamber and turned into gobal warminizing fumes. In this case, the head gasket may be at fault. A compression test can tell you if its the head gasket. It would be a big leak.

If its the lower intake gasket, coolent would be either squeezing out the water jackets to the very front or very rear of the engine (you would see coolent on the ground, down the side of the block), or the opposite way directly inside of the engine. I'm sure it wouldnt get sucked in and burned this way, the coolent jackets have a good inch between them and the closest intake port. But a hunch tells me you may be having a different problem

2) Into the engine due to a cracked head. This will not be obvious, and it could also mean your coolent is going directly into your oil... not good, engine bearings tend to scorch when water is used in place of oil. I believe this may be your problem since you mentioned the problem started after overheating, with this the coolent leak wouldnt be huge, simular to how you describe it.

I say try a compression check. If compression is good in all 6 cylinders, id put my money on a cracked head. If retorqing the lower intake doesnt help and you end up removing the lower intake, you might aswell take the extra step to remove the heads. Have them magnafluxed by some shop (you could pretty much do this yourself... big magnet + fine, fine, powder-like metal shavings). 4.0 heads are prone to crack just about anywhere: deck surface, between the valve seats, on top around the intake ports... its anyone's game.

Having the heads checked/cleaned without much additional work you are looking at $300 to have a fresh top end ($150 in gaskets, $150 in head work), considering you do it youself. If the heads require welding (due to a crack), and new valve guides... (since they are probably bearly holding back oil at this point in their life, stock heads?) you might aswell get a new set of heads. The aftermarket castings are usually better anyway.

Now if you just wanna retorque the lower as a test, its really not that difficult.

First remove the upper intake, this should be pretty straight forward... all the sensors, intake tubing, vaccume hoses, and throttle cable have to go.

From there i believe its 6x 15mm nuts that fasten the upper. There will be a small gasket between the upper and lower, if it comes off in once peice you can probably re-use it.

From there you should be able to reach the 8 nuts/bolts that clamp down the lower intake. The bolts are 10mm, and then nuts are 13mm (i think). I always torqued mine in 3 steps using the specs that came with the Fel-pro gasket set. 8lbs-11lbs-14lbs if i remember correctly. I may be wrong on this as i'm describing it all from memory, the Haynes manual will have these specs laid out.

Good luck...