1999 Venture Oil Pump or oil pressure switch

[joeshannallie]

I did not check the oil pressure. I also did not take off a main cap. No one around had a oil pressure checker. I did not know of any other way to test. Hopefully it will fire up like a new one today. I want to thank everything for their replys, it is greatly appreciated. It just does not make sense. Oil light came on and instant miss and jerk. Maybe today will be my lucky day. Dont like doing things on Sunday but you gotta do what you gotta do. Will update later this evening.

[joeshannallie]

Well after days of making sure I was doing everything right, The problem is the same. Now it cranks and will start but feels like it is very tight when it cranks. Guess battery died(weird did not crank it much) Took belt back off and turn it over by hand and it was the normal tightness thru the compression and then easy until back to compression. So I am at a loss here as what to do next. I guess I could put new plugs and wires on it. Plugs in it are less than 6 months old. Took them out and checked them and they all were right at 60 for the gap. Oil light is still on. I guess it is time to fix the busted brake line on the Grand Voyager and let this one sit. Tired of throwing money at it. Can anyone think of anything at all else to check or try? When it was started today it sounded like the rockers were making alot of noise. But the bad miss was still there. I guess the reason I was thinking it was something simple is because it all of a sudden, Oil light came on and the instant miss and jerk?

[joeshannallie]

Well after lots of reading, It has me thinking it is bad lifters. How can lifters go bad? The old oil did not look the best but it was due for change. There was no metal that I could see in it or none in the bottom of the oil pan. This may be a really dumb question but can the lower intake gaskets be reused? They are less than 6 months old and they were the best you buy at the time. At least I can probably take this engine apart now with my eyes closed!! LOL!

[Blue Bowtie]

Once the intake gaskets are crushed into place during installation, they cannot be re-used safely.

[joeshannallie]

Thanks. That is what I thought. In your opinion could it be a lifter or lifters? Is there anything special I need to do when I install the new lifters?

[Blue Bowtie]

Even if the lifter bores are worn and lifters are leaking down excessively that is usually not sufficient leakage to cause low oil pressure. It might be a good idea to connect a mechanical gauge to the oil pressure sensor port to monitor actual pressure while starting and while the engine runs and warms up. Pressure at cold and hot idle and pressure (hot) at about 1500-1800 RPM could be revealing.

I asked if a main bearing cap or two might have been removed while the pan was off since that's a fairly good indication of the rest, as well as the crank journals. I know it's too late now, so an oil pressure test might be the next best indication.

As for the plugs and wires, you already inspected the plugs and checked the gaps, so that won;t be necessary. The wires can be disconnected and tested while in place. 1500-2500 ohms per foot of length is common. Open wires or those in the megohms are a potential problem.

[joeshannallie]

Thanks. It will not idle long to check anything. Only way it stays running is by giving it gas and then it does not really want to stay running. As soon as you let off the gas it jerks and dies.

[joeshannallie]

Update! The engine now is seized. I took a plug out and the belt off and put a ratchet on the harmonic balancer and it will not budge. Now my questions are, Would a bad main or rod bearing cause my oil light to come on and cause the bad misfire? How does that happen? I see where it is possible to change the bearings while the engine is still in the van. I am tempted to go for it. Only thing I got to lose now is about $40 for the bearings and time! Looks to be easy to do. Just have to take my time and not be careless. Will update again soon.

[Tech II]

You really need to take ALL THE PLUGS OUT, not just one......then try to rotate the engine manually....it's possible the engine is hydrolocked......

If the engine is seized because of bearings, chances are the crank is shot....could also be cam bearings.....connecting rod bearings.....better off with another engine, if the vehicle is worth it.....plenty in the junkyards, with low mileage on them....

[joeshannallie]

Thanks for the advice.

[joeshannallie]

Got the oil pan back off and checking the bearings and I guess I found the reason the engine seized up. Look at the pic and please if anyone knows please tell me what would have caused this. The bearing in the pic is the first main bearing from the front of the engine near the harmonic balancer. Also the rod bearing after this main is seized up to the crank. What would cause this? Just high miles and time for it to wear out or what? Also how could this have contributed to my oil light and bad misfire? Please reply soon.

[Blue Bowtie]

Possibly cascade event. When one bearing fails (especially a main) the debris from it can clog the oil galleries in the crank that feed adjacent rod bearings, and thus starve those bearings until destruction.

Also, once a bearing fails and clearances become too great, maintaining oil pressure is nearly impossible.

Unfortunately, even a complete crank kit may not repair the damage since rings and lifters were probably also oil starved. A used/lower mileage engine might be a good option. Fortunately, the 60° Chevy V-6 is plentiful from many years of production. It might actually be easier to exchange a complete engine/transaxle assembly, but this becomes a bit more tricky since the trans must match the vehicle's PCM. Most good salvage yards should have an interchange guide to identify compatibility.

[joeshannallie]

Thanks for the advice. That is kind of what I was thinking. Because something caused the problem to begin with. I may just take it on apart and remove the block thru the top and rebuild it. Sure do not have the means to take it out thru the bottom. May just chance it and replace the bearings thru the bottom and replace the lifters and see what happens. Then again may just junk it. Really disgusted with it right now.

[mjgrantham]

If you're wanting to keep the van, I too would suggest swapping the engine with a lower mileage replacement. I think it's a much better bet over trying to rebuild yours, especially since you don't know the extent of the damage. This engine actually will fit out the top with the exhaust manifolds (and some other stuff) removed first. This saves from having to disconnect & reconnect the steering gear, suspension components, etc, and having a front end align. I found detailed instructions online, but can't get them right now to link for you. That said, I know just how it is to be determined to find the cause of the problem just to know you solved it, and fix it yourself. I did the same with my Venture on many things, then finally on a tranny problem, I just couldn't figure it out myself. I reluctantly had it towed away after two years of not being able to fix it (took the starter and lots of other parts for my Montana though). Keep that new oil pump, maybe put in the new motor before installing it.

[joeshannallie]

Well after replacing the main and rod bearings the problem is still the same. I did the bearings with engine still in the van. Not all that hard to do, Just very time consuming. Plastigage the crank and it showed still within spec. Crank looked fine. Still no oil pressure. Took the new rebuilt oil pump apart and put vaseline in it to help with the prime(saw it done on many web stories) oil light is still on. Someone told me it was more than likely the camshaft bearings. Cant do that with engine still in the van, LOL! It has new oil pressure sending switch. Anything else at all it could be? I am a expert on taking a 3.4 apart now forsure. Anyway to check the camshaft without tearing it all apart again? It is hard to give up when it seems it should be something simple.