Mechanics

WHEN PASSING A VEHICLE THE OTHER DAY MY OIL PRESURE DROPPED QUITE LOW NOW ITS ABOUT 60 AT START UP BUT ONCE ITS WARMED UP ITS DANGEROUSLY LOW

2000 Chevrolet S-10 • 150,000 miles

The other day while passing another vehicle my oil presure dropped very low so low that it cut the fuel pump off. Iwas able to get it back started and get the mile and a half home taking it easy now when I start it the presure is fine to high but once it warms up its at about 18-22 whan driving and and about 2-7 when at a stop once its realy warmed up recently I changed the head gasket so I looked all around it and the vavle cover gasket and no leaks oil level is where it should be but went ahead and changed the oil and filter just cuz thought that would be a cheap fix and it was time to do it about anyway. The person b4 me that had it realy slacked on the oil chages which was evident when I took the head off and had to clean out all the gunk around the rokers pushrods etc. I have heard the oil pumps inese s-10 are " bullet proof and a; most never shit out so am I looking at a posible clogged screen or something more serious like a rear main bearing or something. Also the last time I was on here it turned out to be the timing chain and tensioner and the fuel pump to totally unrelated things went out at the same exact tim? What are the odds so those have both been changed to in the last month along with 4 out of 8 push rods when I did the head gasket cuz they were showing sighns of wair ar the tops where they meet the roker arms all the advice I can get would be greatly appreciated. Ohh and somebody said something 2 me about a oil presure switch does that control the pump in any way on my 2000 chevy s-10 2.2 auto rear wheel drive?
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Jacob62
May 2, 2012.




The pressure switch keeps the pump running. Manually check your ioil pressure when warmed up. That way if it's good then it will be an easy fix. Whee did the junk go that you cleaned up? In the oil pan? Then it might have clogged your pump screen. Which if this is a 4wd it's easier to pull the motor than to take pan off in truck.

Hmac300
May 2, 2012.
Ok had to pull motor cuz rian it 8 inchs means might aswell just pull it its 2wd but still u cant lower pan without raisn it at least 8 inchs more like 10 but that wouldn matter anyways cuz whoever had it b4 me was an idiot and instead of usinf a gasget he lierly epoxyed the pan to the engine so I had to pull it torqe converter and all since I couldnt get the pan off at all until it was pulled. Pump screen clean a few pieces of plastic frome the timing chain tensioner that got ate up about a month ago on that fix but that was it and lil gunk og old oil but ive seen alot worse. Pump gears seem tight and show no wair impeller that meets with cam shaft shows no wear either but the damn felpro head gasket that I had put on obviously is a piece of shit because even tho my maiting surfaces were spotless and not warped or anything it showed sighns of oil leakedge ( very slight hardly any but still could see the sighns of it)in 3 out of four cylinders and a lil in the coolant( and I torque them to specs and in the proper chiltons order 43 for short bolts 46 for long then plus 90 degress for all of them) so wtf guuess perma seal shit aint all that great and maybe next time il have to over torque a tad or was it just a faulty gasket. Idk. My question now is could that slight leakedge cause that loss of oil presure? Because the head gasket that was in there b4 was in pretty bad shape nut no presure drop I only changed it cuz I noticed a tiny tiny bit of oil in the coolant and I love workn on cars and trucks and like my shit to be perfect. Are there any specs for the oil pump so I could check it out other than the 56 psi at 3000 rpm thing cuz since its pulled I cant exactlt check things out. Oh the sender was fine its #'s matched the mechanicle gauge within about 2-5 psi. But I have to get a new one now anyway since I cracked the damn thing while pulln the motor I accidently grabed it while jiggling the motor foward to get the damn thing out with the freakn trqe converter still atached. I mean epoxy are u kidn me? Good news I found where a oil leak was comn from. Not the rear main seal but the lil 3 bolt on plate at the back of the came shaft the three bolts were barly even finger tight so that explains the oil all over the startere etc. Oh the bearings didnt look worn really either maybe a lil but since its pulled im guna change them. Anything else I should do while its pulled any advice would be greatly aprieciated this is my first engine pull for myself iv helped ppl b4 but never all by my self so ty in advance for any advice or insight : )

Tiny
Jacob62
May 4, 2012.
Wait so if that presure switch was clogged it would not let the pump run all the time? But how would you explain high presure at start up. Wouldnt that mean its running at start up but then somehow stopping once it gets warm? That doesnt quite make sense to me?
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Tiny
Jacob62
May 4, 2012.
No the head was off when o cleaned the gunk out. Im not an ase mechanic but im not an idiot either I wouldnt just let it fall down in there. But there was left over bits of the timing chain tension that got ate up from when the timing chain broke but no pieces made it past the screen that io can tell and even if they did they are plastic its a 2 metal gears type pump so it would chew the shit out of any thing thats not steel or not to big. Is there anything on the pump thats fails that I should be checking or is it probllt the gasket that was causing that presure loss. That seems like alot of presure loss for just a slight leak in a gasket to me?

Tiny
Jacob62
May 4, 2012.
My oil pump is mechanical driven by the cam shaft so its pumping all the time the only faster or slower it gets is with rpms presure switch is actually just a presure sensor I dont think it caauses any thing to "switch" pleas correct me if im wrong?

Tiny
Jacob62
May 4, 2012.
Oen of the tings that can happen is the pressure relief valve sticks and gives you low pressure as well. You can check that for junk in it, but take a look at all the main androd bearings while you have it out. If you can send apic of them while in engine, meaning don't takethem out of the caps I can give you a better idea of things. Obviously the guy that had this before you was well aware of what was wrong with it and that is why he sold it.

Hmac300
May 4, 2012.
Ok that presure relief valve spring loaded thing was stuck took sum working around a bit but got it back moving freely i'm curious if my bearings are in need of replacing for the 60 bucks I should probally just do them but im a lil broke right now. Good news is they honered the head gasket waranty and gave me a free new one. The bearing dont look that bad to me the only wear they shoy is a slight bit on the bottom obviously from cold starts but its minaml when u look at what would be the sides of the bearings there is absolutly no wair at all but il take some close up pics of them and post and get your opinion but I think that or something else was done recently cuz the rear main seal is so new I was able to get it out and its still perfect where I can reuse it which is something I would normally never even consider doing(reusing a gasket). Oh when I bought it I new it needed a head gasket and the timing chain was making noise thats why I paid 1900.00 and book is 3800.00 cuz to me my labor is cheap and parts for these thing are abundent and cheap so figd wtf I just fix anything wrong with it but the guy def slacked on the reg maintenence which sucks cuz reg maintenec prevents all this type shit ya know. Pics to come soon ty again : )

Tiny
Jacob62
May 5, 2012.
Ok pretty sure I found the problem the 3rd main bearing from the front is f'd wore dwon 2 almost nuthing no oil channel left at all but whats wierd is every other damn bearing in the engine is almost like new and they only sell the mains in a set so even tho I only need 1 I have to buy the whole set about $65 checking now to see "why" it failed going to make sure the oil passege way to that bearing isnt logged or something but from what it looks like the "hole" in the bearing got sealed by the melted (silver maybe)idk what it is the outter part looks like copper though so pretty sure this was the problem. Another question what can I use to very gentle polish the crankshaft this on has some very slight scoring but measures within factory specs so high #ed sand paper or what?

Tiny
Jacob62
May 6, 2012.
If the crank is still good which I kind of doubt but y use some 600 grit paper to polish it. Tape a pieceall the way around the journal then take a long piece of leather, wrap it around it a couple times then move back and forth that will polish it right up. Normally when this happens though you need a crank kit which is a reground cranks with bearings.

Hmac300
May 6, 2012.
Well it doesnt seem that bad from what I read online if your finger nail doesnt "catch" or drag it can be slightly polished and mine doesnt catch but I have to get a measuring device regardless to make sure its within factory specs or its time to have it ground and and oversize bearings but really hoping its all good with my buddys c clamp looking measuring device it wa within specs but with that its hard to tell if your centered I measuredin a few spots though and seems good but I would like to find a more acurate way to measure maybe somekind of digital laser deal or something whats the most acurate way to measure the journals?

Tiny
Jacob62
May 7, 2012.

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