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Rick, in both of my Express vans, the lower intake manifold gasket failure resulted in coolant leaking overboard/externally, and was visible on the forward and aft face of the block-to-manifold mate line/joint. There have been other folks on the forums who had coolant leaking internally into the oil, and another guy had the coolant leak into a cylinder, which resulted in a bent rod and a totaled engine.
In my case, it was quite difficult to actually see the leak because it is obscured by all the accessories on the front of the engine, and you have to remove the engine cover to see the aft side of the engine block. I was able to see witness drips the bottom dead center of the timing chain cover. Those drips originated from the manifold-to-block joint and ran down to the bottom of the engine. Most of the coolant will evaporate during operation of the engine, and won’t leave much residual coolant as evidence. If you do a coolant system pressure test, you should see the coolant leak out but, again, you will need to remove the accessories on the front of the engine to be able to get a visual. If you have access to a borescope, that can help.
Peter, thank you for the detailed feedback on failure modes. So... as of now, the van is running fantastic; I had no signs of coolant in the oil when I changed it recently; I had the engine cover off, and the rear of the motor was dry. What I can see of the front also looks dry, so I think it's good for now. I have yet to put tags on the van, so it hasn't been driven much since we got it. It's looking like this week we may get the van inspected and registered. Once the van is in service, I will be putting the coolant level checks on a "recurring inspection schedule"...
Today my neighbor came through with four FREE wheels and tires from a 1994 Silverado. The tires have ~1000 miles on them. The tires that were on the van when we bought it were a combination of "Blacklion Voracio??" on the front and some OLD Mastercraft tires on the rear. All the tires had good tread left on them, but the Mastercraft tires had some pretty bad dry rot splits in the sidewall.
The backstory on the wheels/tires is that I sold my neighbor that Silverado about 4 months ago. I had those tires put on about a year ago and then parked the truck. My neighbor decided to take the Silverado in a different direction, lower it, and put some staggered low-profile performance tires on the truck. I realize the Bridgetstones are AT's, but I am still happy to have them, and now the van is ready to put into service. I hope to get it inspected and registered this coming week.
I had a Vortec 4.3 with failed intake gasket. It happened gradually, not catastrophically. Seepage was visible from the exterior. Surfaces were pitted. I just replaced the gasket and it was fine.
It would have had around 150,000 mi on it
Last edited by mountainmanjoe; May 21st, 2020 at 4:16 PM.
I had a Vortec 4.3 with failed intake gasket. It happened gradually, not catastrophically. Seepage was visible from the exterior. Surfaces were pitted. I just replaced the gasket and it was fine.
It would have had around 150,000 mi on it
I don't want to do it, but I have a feeling that the job may be in my future...
On another note, the Corona Van FAILED Maryland inspection today... bummer. There were two issues: 1) Evidently the PO used compression fittings to repair the front brake lines (I did not know this), and 2) the rear bumper has rust holes in it. I let the inspecting garage fix the brake lines, but they wanted too much for the bumper; I will be replacing it myself... So it looks like one more week until we get the van on the road.
for the intake gaskets...try to source steel-framed gaskets instead of plastic.
Steel gaskets, copy. I feel like I'm already almost out there in the driveway doing this job... I feel like it's inevitable. Although I keep saying I don't want to do this job, maybe deep down inside I really do want to do that gasket. I mean, how many times will I get a chance do the notorious 5.7 L31 lower intake manifold gasket? And in an Express van? It sounds like a great challenge. I still don't want to do it...
I usually don’t fix things till they break, but since my van is intended for road trips, I wanted to replace as many little things as I could preemptively.
Especially little things under the dog house.
So the radiator, water pump, and heater valve were all leaking. While in there I replaced all the hoses and radiator cap.
it only took a couple weeks for the newly pressurized system to find the next weak spot - the intake gasket.
mine is a 95 so a little different but better to replace it now when you have time.
I had an intake bolt head snap off too. Was an adVANture.
May 15th, 2020, 5:03 AM
