I need to get some things strait for myself. I have a bad intake gasket, I'm not sure about the head gaskets. I'm losing a very small amount of coolent (I have to top it off every week and a half or so), so I've been living with it till I can get something done about it. It has a leak form the front left and rear right which I think I heard was common, and someone made the comment the many head gaskets have been "misdiagnosed" becaue of this. when I start it up it idles rough for a few seconds I attributed this to a small amount of coolent leaking into the cylinders after shutting her down. There is no coolent in the oil and an external leak so would it be a good idea to just do the intake gasket? I'm sure I can do that so it would just be parts cost. Is there a way to know if the HG is bad with the intake off?
also the valve rockers look pretty gunked up( I noticed through the right valve cover hole) is there a way to heavaly clean them without taking the heads off, like spraying them with seafoam then draining the oil, or should I leave well enough alone. Thanks guys.

 

Does it smoke out the tailpipe? start it up and go back there and sniff that exhaust pipe... if it smells sweet, like coolant, you may be up for a head gasket... I just had mine done, white smoke was coming out the back and it smelled like burnin coolant. it doesnt smoke now and no sweet smell from the exhaust...

 

That sounds like bad headgaskets. When you have have leaks at the front or back corners of your engine chances are it is the headgasket because the coolant runs down the front and the back of them and when they get warped (aluminum heads and all) there is only a very thin piece of gasket and it usually leaks.

As far as your intake manifold gaskets go there are 2 the upper and lower (valley pan) and sure you get leaks from those too and from a couple other places (throttle body heater plate, top hose and any other random coolant hose). The only way to know for sure is to find the leak but that can be hard because there is so much crap in the way in the front and rear of the engine. If you want to know for sure take it to get a pressure test and have them poke around with mirrors and lights.

An induction cleaning with Sea Foam will make the leak worse. You probably have some gunk acting as clots and the seafoam will clear them and the coolant will pour out. Ask me how I know and I will tell you I just replaced my head gaskets and am working on getting the other pieces together now. The upper manifold gasket is a cake walk, the lower is tougher and the head gaskets are a b!tch.

 

I'd do a compression test, that will often reveal head gasket defects.
You could just replace the intake gasket and see if that fixes the problem, it's only about $15 in parts assuming you don't end up needing a new fuel rail too, like I did, which would be another $95. But if you need one, you'd need it doing the heads anyway.

 

The tried and true test, is a coolant pressure test, pump it up to around 18#s and watch the gauge for 15 to 20 minutes, if you have a leak, and you say you do, then the system will leak, internally or externally and confirm. Any leak, especially at your miles should be delt with ASAP and with your mileages, I would say it is time to do head gaskets.

 

Coolant pressure test works for coolant leaks, but is useless for compression chamber gasket leaks. Since he can see the coolant leaks, I don't see much value in doing a coolant pressure test.

 

I disagree, even though you don't see the coolant leaking into the cylinder, if the gauge is left on and you see the pressure drop, be it outside and down the block or inside, it is still a leak and has to be delt with. If you don't see coolant leaking around the block, and your engine can't hold pressure it has to be head gaskets leaking internally.

 

Right, but he already sees the coolant leak, so there's no value in doing a pressure test. A pressure test won't tell him if he also has an internal leak or not, so there's no point in doing it.
If he said, "I'm loosing coolant but see no leaks." then yes, a coolant pressure test would be of some value.

 

yes, I know it is leaking externally, so would a compression test tell me if its leaking internally also? if so how much should I expect to pay for that?

 

Well if you want to avoid the cost and hassle of doing your head gaskets you need to find out where it is leaking from. So buy a little mirror/light on a flexible cable from harbor freight and start looking. Otherwise you may be just be wasting your time with replacing the upper intake manifold gasket if you have to do it again. Like I said if may be your valley pan gasket, mine was pretty trashed.