Throttle stuck and now the engine won't stay running.

[Zedyone_kenobi]

That is a head gasket. I have seen that coffee creme color before on two different V8's I have owned. Start planning a new head gasket install and also decide what you want to upgrade while you are in there.

[madkaw]

Go to autozone and borrow their coolant pressure tester. Basically it just fits where your radiator cap is and follow the instructions. You run the car and watch for build up pressure beyond the cap rating. If it builds then starting pulling spark plug wires one at a time(while running) to see if it stabilizes the pressure. If pressure builds then you have a blown gasket, and pulling a plud will verify which cylinder and that the gasket is blown.

[Gary in NJ]

Can a head gasket be blown and still show relatively good compression?

Well that's the problem with a basic compression test, I can't tell from the values if it's good or not. All I can infer it that the compression seems to be even across all six cylinders. The slight dip on the number 5 cylinder is of little consequence and within the margin of error in the test itself.

Further, you can show "good" compression on that test, yet still have a leak at the head gasket. The water that "fills the void" isn't compressible. Head gaskets just don't leak to the outside world, they also leak into the water jackets. This is what I suspect is happening on your engine.

Given that you may have over-reved the engine and floated the valves, I would have the valves inspected to make sure that they are still within spec. Also, when you have the head off the engine look for any places where the valves have made contact with the pistons.

[M.Gwizdek]

Well that's the problem with a basic compression test, I can't tell from the values if it's good or not. All I can infer it that the compression seems to be even across all six cylinders. The slight dip on the number 5 cylinder is of little consequence and within the margin of error in the test itself.

Further, you can show "good" compression on that test, yet still have a leak at the head gasket. The water that "fills the void" isn't compressible. Head gaskets just don't leak to the outside world, they also leak into the water jackets. This is what I suspect is happening on your engine.

Given that you may have over-reved the engine and floated the valves, I would have the valves inspected to make sure that they are still within spec. Also, when you have the head off the engine look for any places where the valves have made contact with the pistons.

I understand how a leak down test would allow me to zero in on the cause. Thank you for the information. Unfortunately in my case it is pretty clear that the head needs to come off. I will definitely take your advice and will have someone check the valves.

It will probably take me a bit to get the head off as I'm traveling, but when I do I will post some pictures and update you on what happens. If anything it will be good to follow up so others who find this thread can use the information.

Thanks again to everyone for reading and replying.

Mike

[M.Gwizdek]

Hey Guys,

It's been a few months but I was finally in town long enough to pull the head off to replace the head gasket. I noticed a hole that allows coolant to leak directly into the valve train area. It is located right above the thermostat housing mount. I've pointed to it in the picture below.

I'm at a loss as to what happened. Any ideas? Can this be fixed?

Thanks,

Mike

[mjr45]

I don't know for sure but I suspect you'll need a new head. Aluminum welding can be spendy and I doubt you could ever get the head perfectly flat after a weld job. The hole in the head is probably going to be a lot bigger than it appears. If it was me I would find a used head, have it rebuilt and go from there with no more worries and will probably cost you less in the long run.