Oil pressure problems
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Joined: Sep 2003
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From: Colorado
Oil pressure problems
I am currently experienceing what I believe is an oil pump problem with an '88 Bronco, 302 v8 with 122k miles.
I just bought the vehicle from an auction, it's in pretty bad condition, but it's almost back to a good running state (replaced several things from an ECT sensor to a cracked manifold). After those and some other repairs, the vehicle is running a lot better, but still not running all that great.
The following problems are most evident right now:
-It gets REALLY hot REALLY fast. After starting it, not even a mintue later the exhaust manifold is too hot to touch
-At idle (right now its idling at about 600 RPM when warmed up), the oil pressure gague (this is the dash gague, I haven't checked it with a shop gauge) goes to zero and the "Engine" light comes on, but then returns to normal presssure when RPM is over 2000 and the light goes off.
-Once the engine is hot, if you let it sit at idle for a few mintues it will start to smoke out the exhaust manifolds and buck like it has no oil (when it has a full oil level)
-It's running a little rough and failing emissions with high HC (possibly because it's so hot i'm getting a pre-ignition?)
...okay, so it obviously is having some kind of oil problem. It would be really nice if all I had to do was do a flush out the engine and then replace the oil pump and screen, etc...
However, when I changed the oil it was blacker than night, and the filter felt like it had a brick in it. I'm afraid that the engine has been run in this condition for a long amount of time by the previous owner, and that an engine rebuild may be in order.
Any thoughts about this would help, specifically I'm looking to see how probable it is that the engine is seriously damanged and needing a rebuild, and any recommendations for getting the oil pressure back to normal.
Also, if someone knows how to check the pressure with a shop gauge that would be grealy appreciated.
Thanks,
Robert
I just bought the vehicle from an auction, it's in pretty bad condition, but it's almost back to a good running state (replaced several things from an ECT sensor to a cracked manifold). After those and some other repairs, the vehicle is running a lot better, but still not running all that great.
The following problems are most evident right now:
-It gets REALLY hot REALLY fast. After starting it, not even a mintue later the exhaust manifold is too hot to touch
-At idle (right now its idling at about 600 RPM when warmed up), the oil pressure gague (this is the dash gague, I haven't checked it with a shop gauge) goes to zero and the "Engine" light comes on, but then returns to normal presssure when RPM is over 2000 and the light goes off.
-Once the engine is hot, if you let it sit at idle for a few mintues it will start to smoke out the exhaust manifolds and buck like it has no oil (when it has a full oil level)
-It's running a little rough and failing emissions with high HC (possibly because it's so hot i'm getting a pre-ignition?)
...okay, so it obviously is having some kind of oil problem. It would be really nice if all I had to do was do a flush out the engine and then replace the oil pump and screen, etc... However, when I changed the oil it was blacker than night, and the filter felt like it had a brick in it. I'm afraid that the engine has been run in this condition for a long amount of time by the previous owner, and that an engine rebuild may be in order.
Any thoughts about this would help, specifically I'm looking to see how probable it is that the engine is seriously damanged and needing a rebuild, and any recommendations for getting the oil pressure back to normal.
Also, if someone knows how to check the pressure with a shop gauge that would be grealy appreciated.
Thanks,
Robert
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Joined: May 2002
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From: Chicago Area
There is often a pipe plug in the oil filter base casting for oil pressure testing. If not, you will have to remove the OE oil sender which is usually also in that location. But it sounds like your OE gauge is probably correct, so I'm not sure what the point is.
Sometimes using a heavier and/or straight weight oil (like SAE 50) will get the oil pressure up. That's the theory behind the additives like STP, etc. If a lot of oil is getting past the rings or valves, that would also account for your high HC's.
I wish I could give you some good news, but it sure sounds like you've got a worn out engine. Maybe someone else can suggest some other "band-aids"!
Sometimes using a heavier and/or straight weight oil (like SAE 50) will get the oil pressure up. That's the theory behind the additives like STP, etc. If a lot of oil is getting past the rings or valves, that would also account for your high HC's.
I wish I could give you some good news, but it sure sounds like you've got a worn out engine. Maybe someone else can suggest some other "band-aids"!
Post Fiend
Joined: Jan 2003
Posts: 8,600
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From: Iowa
I'd try some 20w50 first. That should make a little difference. I've seen 70 weight racing oil around, maybe that could be a last ditch effort...
Try taking all the belts off and pulling the end of the crank around in every conceivable direction. If it moves, the bottom end is shot. No weight of oil will fix it at that point.
Hook up the mechanical gauge to see what pressure you're getting.
I know it sucks, I had a 2.9 out of a bronco2 shuck out. Good luck!
Try taking all the belts off and pulling the end of the crank around in every conceivable direction. If it moves, the bottom end is shot. No weight of oil will fix it at that point.
Hook up the mechanical gauge to see what pressure you're getting.
I know it sucks, I had a 2.9 out of a bronco2 shuck out. Good luck!
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Joined: Sep 2000
Posts: 7,298
Likes: 45
From: Southern California
I would first make sure the cooling system was operating correctly. Make sure it has the correct thermostat and that the coolant level is not too low. Remove the radiator cap while it's cold and start the engine to observe if the water pump is working. If it is, you should see some motion in the coolant. This is also a good time to observe if the head gasket's are leaking. A leaking head gasket may show gas bubbles and an oily sheen in the coolant. A leaking head gasket can make an engine run hotter because gas bubbles in the coolant interfere with the radiator cooling and the radiator can't hold pressure because it's always venting out the cap. Also, if your new oil takes on a mousse-like consistancy and color, that would indicate a head gasket leaking coolant into the oil.
Get a timing light and check to make sure your ignition is advanceing properly. It's a small chance, but a retarded spark will make an engine run hotter.
While not disagreeing with the advice given about heavier oils showing better pressure, I would say in this case it might be better to go with a lighter oil like 5w30. The reason I say that is because you believe the oil pump pickup screen may be plugged. A heavier, more viscous oil will have a harder time getting through a restricted suction screen and could make the pressure even lower by starving the pump.
I'm not a big fan of engine flushes, but in this case while you may be considering a rebuild anyway, you have nothing to lose and everything to gain. I'd first confirm that the engine is heavily sludged by removing one of the valve covers to inspect underneath. If you do an engine flush, and depending on the results, I would at least pull the pan and check the oil pickup screen and pump before doing a rebuild.
Get a timing light and check to make sure your ignition is advanceing properly. It's a small chance, but a retarded spark will make an engine run hotter.
While not disagreeing with the advice given about heavier oils showing better pressure, I would say in this case it might be better to go with a lighter oil like 5w30. The reason I say that is because you believe the oil pump pickup screen may be plugged. A heavier, more viscous oil will have a harder time getting through a restricted suction screen and could make the pressure even lower by starving the pump.
I'm not a big fan of engine flushes, but in this case while you may be considering a rebuild anyway, you have nothing to lose and everything to gain. I'd first confirm that the engine is heavily sludged by removing one of the valve covers to inspect underneath. If you do an engine flush, and depending on the results, I would at least pull the pan and check the oil pickup screen and pump before doing a rebuild.
Last edited by horsepuller; Sep 26, 2003 at 02:21 PM.
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Joined: Oct 2002
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Look down the oil fill cap into the head. If you can see anything down there, look to see if it is covered in crud. You can even poke something into the goo and see how deep it is.
If you already changed the oil and filter then you can add a couple of quarts of Type F auto tranny fluid ( don't overfill it, take out a quart or so of oil) Then start it up and let it run at 1500-2000 rpm for at least 30 min to hour. ( Watch the temp guage and hold your nose if it smokes too much.)
This stuff works as good or better than any flush I ever saw. The detergents in it will eat most any kind of sludge out of passages and oil pickups. You have to use it with new oil and filter though cause you want to wash out all the old crap you can get. Once you get done shut it down and check the oil. (Watch the oil press and level while your doing this in case it burns it all up you don't want to seize something.) Look inside the cover and look at the oil. It should be cleaner inside the engine and the oil should be black and nasty. If you want to you can also drive the engine around a little like this. Just don't run it real hard because this oil will be pretty thin. Then change the oil and add a good 10w-40 or 20w-50 name brand oil and check the pressure etc.
If this doesn't work there are numerous threads around here that will help you either do the job right, or cheap it out until you can afford to do it right. Try to stay away from running gear oil in the engine. Although it can be done, it doesn't mean that it works forever or that your engine won't blow up if you do it.
If you already changed the oil and filter then you can add a couple of quarts of Type F auto tranny fluid ( don't overfill it, take out a quart or so of oil) Then start it up and let it run at 1500-2000 rpm for at least 30 min to hour. ( Watch the temp guage and hold your nose if it smokes too much.)
This stuff works as good or better than any flush I ever saw. The detergents in it will eat most any kind of sludge out of passages and oil pickups. You have to use it with new oil and filter though cause you want to wash out all the old crap you can get. Once you get done shut it down and check the oil. (Watch the oil press and level while your doing this in case it burns it all up you don't want to seize something.) Look inside the cover and look at the oil. It should be cleaner inside the engine and the oil should be black and nasty. If you want to you can also drive the engine around a little like this. Just don't run it real hard because this oil will be pretty thin. Then change the oil and add a good 10w-40 or 20w-50 name brand oil and check the pressure etc.
If this doesn't work there are numerous threads around here that will help you either do the job right, or cheap it out until you can afford to do it right. Try to stay away from running gear oil in the engine. Although it can be done, it doesn't mean that it works forever or that your engine won't blow up if you do it.