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Discussion Starter #1
Lost oil pressure in my car end of last year and I’ve since parked it. Will still start, didn’t over heat, no knocking etc. Pulled the sending unit out and started car quickly to see if any oil was pumping out, but no oil. Assuming it’s the oil pump, I’ve read it seems to be just as much work to pull the engine as it is to mess around with removing the front timing cover and or the oil pan, so my question is... those that have pulled one of these engines, are the instructions in a Haynes manual good enough to go off of? I haven’t looked at one yet so I’m not sure If they even have a section on pulling the motor. If not, is there a thread and or a how to on pulling it? I’d rather not go in blind, there’s a few videos on YouTube but they’re sub par at best. Thanks in advance!
 

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It's pretty easy to do honestly. I'm sure I'll forget a few steps but in no particular order besides the remove engine part:

-unplug wiring
-unbolt headers at the collectors and remove mid pipe
-remove radiator (leave the fan attached)
-remove power steering pump (leave it in the engine bay attached to the rack)
-unbolt motor mounts from the k member
- unbolt driveshaft from the rear end
- unhook intake
-drain fluids
- disconnect starter wiring
- remove engine with trans attached

Overall it really isn't a bad job to do. I'm at the point now I can have one out in an hour or two.


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Discussion Starter #3
It's pretty easy to do honestly. I'm sure I'll forget a few steps but in no particular order besides the remove engine part:

-unplug wiring
-unbolt headers at the collectors and remove mid pipe
-remove radiator (leave the fan attached)
-remove power steering pump (leave it in the engine bay attached to the rack)
-unbolt motor mounts from the k member
- unbolt driveshaft from the rear end
- unhook intake
-drain fluids
- disconnect starter wiring
- remove engine with trans attached

Overall it really isn't a bad job to do. I'm at the point now I can have one out in an hour or two.


Sent from AutoGuide.com Free App

I have long tube headers so I’m fairly certain I won’t be able to pull the motor with them attached, I’ve heard some you can but I don’t think I can with my macs, need to disconnect or block off the fuel lines or anything? Or would that be under drain fluids? The car has been at the shop for going on 3 weeks and the mechanic has still not touched it so it may be time to take things into my own hands, which I likely should have done from the start as is.

---------- Post added at 11:26 PM ---------- Previous post was at 11:24 PM ----------

Also, need to disconnect the steering shaft? Where do you hook your chains to when hooking the engine hoist up? Sorry for the bombardment of questions, just getting them all out while it’s fresh in my head.
 

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Lost oil pressure and parked it? Did you change the oil pressure switch? The only reason I ask is mine went bad. The oil pressure gauge ( actually nothing more than an idiot light) went to zero. I was afraid to run the motor. I changed the oil pressure switch down by the oil filter and it worked normally.

I have been driving our Corvette for about a week without an oil pressure gauge. Instead of zero (like my Mustang), it fails to 80 psi. I know its bad and if it was the pump I would have blown the motor 500-1,000 miles ago.

Hell, I'd change the $10 switch (you called it a sensor which it isn't) before I'd do anything.
 

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Discussion Starter #5
Lost oil pressure and parked it? Did you change the oil pressure switch? The only reason I ask is mine went bad. The oil pressure gauge ( actually nothing more than an idiot light) went to zero. I was afraid to run the motor. I changed the oil pressure switch down by the oil filter and it worked normally.

I have been driving our Corvette for about a week without an oil pressure gauge. Instead of zero (like my Mustang), it fails to 80 psi. I know its bad and if it was the pump I would have blown the motor 500-1,000 miles ago.

Hell, I'd change the $10 switch (you called it a sensor which it isn't) before I'd do anything.
I called it a sending unit, as in the oil pressure sending unit, which I removed from beneath the engine and started the car up. If there was oil pressure there should have been oil coming out of that hole where the oil pressure sending unit goes. Ideally I guess I’d hook a mechanical gauge up to the car and check the pressure with that, which was what the mechanic was supposed to do, amongst other things. Like you say though for the sake of a cheap part it may be worth it although I’m 99 percent sure it’s not that. Just seems random for an oil pump to fail especially with only 43,000 miles on the car. Although the gears in our oil pumps are made of a shitty metal.
 

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My 99 3.8L also had a messed up oil presser switch. The first time it showed I lost pressure I shut off the car and pulled over. I started it right back up and it showed pressure again. I drove it home got a mechanic gauge on it, and it showed I had pressure. Low and behold it was just my oil pressure switch, replaced it and it did the same thing. I just ignore it every time it goes to 0 and jumps back to pressure. I noticed that I also had a code for my pressure switch when I scanned it with an autel scanner.
 

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Haynes book is pretty good. Don't need to pull engine, least I wouldn't but that's me. I'd get car up to unbolt A/C compressor and steering pump. As they are partially bolted to cover. Then four bolts on front of oil pan that go into timing cover at bottom. Rest can be done with car on ground which makes things easier to work on.

You can pull the valve covers. Clutch cable can make driver cover a pain but can be done without removing cable. Remove anything bolted to timing cover. Pull harmonic damper(an installer/puller tool is great for here if you can access one). If still stock type water pump then it can stay(do remove pulley), which saves having to drain coolant. Then the timing cover can be pulled without pulling engine. After that only things that need to be removed to get to oil pump are the timing chains. If your confident to not turn anything then say hello to pump. Otherwise use service book and before removing chains turn motor over until crank and cams are in proper locations. Will need to compress or remove hydraulic tensioner for each chain to give enough slack to remove them. Note that if these are plastic(which they should be), you can compress without removing. If metal type. They use a rachet lock to keeps them from being compressed. Easier to remove and compress off the motor. A large paper clip then works nice to keep them locked down.

Only four small bolts hold pump to block and two small bolts hold feed tube to bottom of pump which can be removed without pulling oil pan. Just have a magnet handy encase one falls into pan. Tube has enough flex to pop off bottom of pump. Should be an o-ring on end of tube where it goes into pump. Unbolt pump and it just slides off crank/block. You can take pump apart. Few small screws on back plate to remove and then can look at gears inside. Considering the design. It would require an epic failure of pump to stop moving oil. There should be little flats in opening of gear that ride on crank to turn pump. Make sure they are there. If gears look good. Only thing I can think of is pressure relief on pump is stuck open, cycling oil around pump instead of into block.
 

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Discussion Starter #8
Haynes book is pretty good. Don't need to pull engine, least I wouldn't but that's me. I'd get car up to unbolt A/C compressor and steering pump. As they are partially bolted to cover. Then four bolts on front of oil pan that go into timing cover at bottom. Rest can be done with car on ground which makes things easier to work on.

You can pull the valve covers. Clutch cable can make driver cover a pain but can be done without removing cable. Remove anything bolted to timing cover. Pull harmonic damper(an installer/puller tool is great for here if you can access one). If still stock type water pump then it can stay(do remove pulley), which saves having to drain coolant. Then the timing cover can be pulled without pulling engine. After that only things that need to be removed to get to oil pump are the timing chains. If your confident to not turn anything then say hello to pump. Otherwise use service book and before removing chains turn motor over until crank and cams are in proper locations. Will need to compress or remove hydraulic tensioner for each chain to give enough slack to remove them. Note that if these are plastic(which they should be), you can compress without removing. If metal type. They use a rachet lock to keeps them from being compressed. Easier to remove and compress off the motor. A large paper clip then works nice to keep them locked down.

Only four small bolts hold pump to block and two small bolts hold feed tube to bottom of pump which can be removed without pulling oil pan. Just have a magnet handy encase one falls into pan. Tube has enough flex to pop off bottom of pump. Should be an o-ring on end of tube where it goes into pump. Unbolt pump and it just slides off crank/block. You can take pump apart. Few small screws on back plate to remove and then can look at gears inside. Considering the design. It would require an epic failure of pump to stop moving oil. There should be little flats in opening of gear that ride on crank to turn pump. Make sure they are there. If gears look good. Only thing I can think of is pressure relief on pump is stuck open, cycling oil around pump instead of into block.

Basically I was going wide open down the highway in 4th and felt a slight hesitation in the car, now whether that was just a bump in the road or the car itself I don’t know but it was enough for me to look down at the gauges and I realized no oil pressure. Since I pulled the sending unit out and turned the car back on I assume I’m getting no oil pressure. The mechanic seemed to think it was strange for it to fail too and had mentioned that pressure relief that you mentioned. The only thing that sketch’s me out in the whole process is taking the timing chains off. I’m sure im over thinking it but I’d just hate to take them off and some how turn one of the cam gears and mess up the timing.
 

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Im going to bet your oil pump is fine and you just have a shitty oil pressure sending unit - which is super common for that era. Put a mechanical gauge on and see what it reads.

Also, I know 2 valves are pretty easy to pull, but having taken the timing cover off on a previous engine, I can also tell you that it is a very easy job to take the timing cover off.
 

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Discussion Starter #10
Im going to bet your oil pump is fine and you just have a shitty oil pressure sending unit - which is super common for that era. Put a mechanical gauge on and see what it reads.

Also, I know 2 valves are pretty easy to pull, but having taken the timing cover off on a previous engine, I can also tell you that it is a very easy job to take the timing cover off.
Mechanic finally got back to me, zero oil pressure with mechanical gauge, so oil pump is more than likely toast. Mechanic says he can replace the pump no problem but he’s uncertain how long it ran without oil pressure (as am I) And says it’s up to me if I want to gamble with just replacing the pump and hoping I didn’t heat up the rod bearings too much or some other type of damage. Claims he would pull the engine and check it all over and go from there. So not sure what I’m going to do, pay the labour to get him to change the pump and hope for the best or maybe pay extra and get him to pull the pan and check the main bearings etc. The engine didn’t over heat, it wasn’t knocking when i shut it down last year. I’d hate to throw a new pump in, then have him turn the car on and an hour later it’s toast. Then back to square one.
 

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Hmm that is a tough one. Ideal thing would be to pull pan and rod caps and main caps to look at bearings. If you didn't have a knock you could lucked out and not spun a rod bearing but still. The chance of burning up the bearings would put it on borrowed time even with new pump. Be worth the little extra for piece of mind.
 

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Pull oil pan replace pump then go from there.. go small and if need to after wards then go big... of course there is uncertainty but no need in getting to deep until you restore pressure.
 

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Discussion Starter #13
After the mechanic quoted me at 1700 dollars to replace the pump, I’ve decided to do it myself, he can take a hike. I may take an oil sample and send it to the lab at my work and get it tested as well. When installing the new oil pump, do you need to prime the oil pump? I’ve seen on some other motors you hook up a drill to it and prime it that way, most of this seems to be for new engine builds. If mine is just a pump replacement It just needs to be able to create a vacuum I think and I should be good to go.
 

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After the mechanic quoted me at 1700 dollars to replace the pump, I’ve decided to do it myself, he can take a hike. I may take an oil sample and send it to the lab at my work and get it tested as well. When installing the new oil pump, do you need to prime the oil pump? I’ve seen on some other motors you hook up a drill to it and prime it that way, most of this seems to be for new engine builds. If mine is just a pump replacement It just needs to be able to create a vacuum I think and I should be good to go.
I've always poured some oil into pump. Turned it by hand before installing. Just to get everything coated and help with pulling oil on startup.
 

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I probably wouldn't pull the engine either. It's not too bad getting the timing cover off with the engine in the car. Just make sure you label everything well and have a good diagram.
 

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Discussion Starter #17
Not going to pull the motor, got a new Melling oil pump on the way and some new gaskets and going to drop the front timing cover, replace the oil pump, put new oil in and cross my fingers she’s good to go. Obviously the oil pump will fix my oil pressure problem, just hoping the rest of the motor is fine. If it’s not it’ll be time to save for a built one.
 
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