Oil pressure drops
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Oil pressure drops
Hello all,
I'm working on my bronco (obviously) and I have a question. When I bought the Bronco I was told that the oil pressure guage drops to no pressure at an idle when the rig is warmed up. On my way home, I experienced this. Now I currently have the transmission out, and I was going to replace the oil pump, change the oil and fix all the oil leaks while I have it out, but I got to thinking "what if that's not the problem?" So here I am again. Has anyone had this happen to them before? I'm not getting any knocking or pinging or lifter chatter and as soon as the RPMs come up again the oil pressure comes right back up. I've only driven it about 100 miles total in the 6 months I've had it. It's going to be a trail rig though and it has to be a bit reliable. Should I change the oil pump and hope for the best, or should I fix the leaks, change the oil and put another pressure guage on it and see if it's just the guage?
I'm working on my bronco (obviously) and I have a question. When I bought the Bronco I was told that the oil pressure guage drops to no pressure at an idle when the rig is warmed up. On my way home, I experienced this. Now I currently have the transmission out, and I was going to replace the oil pump, change the oil and fix all the oil leaks while I have it out, but I got to thinking "what if that's not the problem?" So here I am again. Has anyone had this happen to them before? I'm not getting any knocking or pinging or lifter chatter and as soon as the RPMs come up again the oil pressure comes right back up. I've only driven it about 100 miles total in the 6 months I've had it. It's going to be a trail rig though and it has to be a bit reliable. Should I change the oil pump and hope for the best, or should I fix the leaks, change the oil and put another pressure guage on it and see if it's just the guage?
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Joined: Nov 2007
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From: Upstate NY
for my dealings, if it has that idoit light type sender, those fail in a short period of time, one sure way is to put a regular gauge on it to see just what you do have. Cause if you did have lifter tict, or a bottom end knock or rap, then you more then likey have a issue. Its not a bad idea to change the oil pump & pick up tube,espically if she's a high miler. But if your going that far might as well throw a set of bearings at her as well. you got the pan off & your there, might as well do it. the only other thing that could bite you is the cam bearings, good oil pressure when cold, but drops off when warm. so there's not really a short cut to any fix, its eather do it, or take what ya get for what ya got. and since you have the trans out if its a one piece rear main seal, change it. my 2 cents
Keep Em' Twistin'! Bob B
Keep Em' Twistin'! Bob B
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Joined: Jul 2002
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From: Bend,OR
first install a mechanical gauge to see what you are at. also make sure your not using a Fram filter. wix,purolator, etc.. are better to use. what grade oil are you using? if its 10-30 you might start running 20-30 or 20-50 oil to see if the pressure comes back
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Thanks guys. Unfortunately the transmission is not currently in the truck, so testing with different weights and putting in another oil pressure guage is out. I really don't want to have to pull this transmission more than once as it's kind of a pain in the a$$. I think I'll just replace the oil pump while I have the tranny out anyway, since I need to replace the pan gasket and the rear main as well, better safe than sorry.
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Joined: Jan 2006
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Your post did not say what year or engine size . If it is a early big Bronco with a 351 or 400 these are historicaly very hard on main bearings due to poor oiling system they came with ,which would cause the problem you are having. I would plastic guage the crank bearings and install .001 oversize if nessary . Also put in a high volume high pressure oil pump to correct the factory oiling mistake . I have a 79 Bronco 351 that I bought new . I got 110000 on it before having the same problem you are having . I rebuilt the engine with a high volume high pressure pump . It now has over 460000 on it on that same rebuild and still running strong with good oil pressure .
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