Troutman Posted October 8, 2007 Share Posted October 8, 2007 im curently seeing higher oil pressures than i would like during inital driving. usually the pressure will climb up to 60-65 psi roughly for the first 5 minutes of driving then gradually work its way down to 45 and remain there once the car is at temp (aisde from stop light idle). unless of course im am on the gas hard and it will take longer. 9 times out of 10 i dont drive the car hard, but the first time i did... now resulted in a leak at the rear seal. the engine has roughly 1200 miles on it since the rebuild (l28 f54/ P79 in a 240) i ran a staright 30w for break in then switched to mobil 1 10w-30. i never had the pressure spike when i ran the staright 30. im curious to know if i should switch oil viscositys or go to a semi-synthetic, etc. to reduce this inital pressure? i live in milwaukee and the car is only driven roughly may-oct/nov so the lowest possbile cold start up would be in the 50s, highest in the 80s. Thanks Todd Quote Link to comment Share on other sites More sharing options...
Zmanco Posted October 8, 2007 Share Posted October 8, 2007 60-65 psi when cold doesn't sound high to me at all. I see ~70+ (based on the gauge which we all know is less than accurate) when cold and when the RPMs are up. Are you concerned that 60+ psi is higher than you used to see before the rebuild? Perhaps your bearings and/or oil pump were worn giving you lower than normal oil pressure, and now that your engine is in good condition again, this pressure seems too high? Based on the numbers you state, I don't think your oil leak is due to excessive pressure, probably improper installation of the seal. The rear main seal is a pain to install. Quote Link to comment Share on other sites More sharing options...
Troutman Posted October 8, 2007 Author Share Posted October 8, 2007 60-65 psi when cold doesn't sound high to me at all. I see ~70+ (based on the gauge which we all know is less than accurate) when cold and when the RPMs are up. Are you concerned that 60+ psi is higher than you used to see before the rebuild? Perhaps your bearings and/or oil pump were worn giving you lower than normal oil pressure, and now that your engine is in good condition again, this pressure seems too high? Based on the numbers you state, I don't think your oil leak is due to excessive pressure, probably improper installation of the seal. The rear main seal is a pain to install. that is a good possibility..thanks for the info. also i am running dual electric fans now on a thermostatic switch, and i may have it set at too low of a temp that does not allow the engine to warm as soon as it should. i figured that the seal probably wasnt in correctly and that the oil leak just confirmed it. i hadnt planned on rebuilding the trans until next winter but i think i may do it this winter to also gain access to the rear main seal. is it a PITA to do the seal while the engine is still in the car? thanks Quote Link to comment Share on other sites More sharing options...
Zmanco Posted October 8, 2007 Share Posted October 8, 2007 is it a PITA to do the seal while the engine is still in the car?Yes - been there, done that. But you may find that it's not the seal itself, but the seals that go between the rear main bearing cap and the block. When I rebuilt my engine the first time, I did a poor job getting the cap sealed. I thought it was the rear main seal and replaced it in the car, but that didn't solve the leak. Luckily (yeah right) I had a chance to rebuild it a second time, and this time paid extra attention to getting those seals in. Haven't had a leak since. I'm not trying to talk you out of it, just saying that it may not be the rear main seal. And I don't think it's practical to R&R the rear main bearing cap with the engine in the car. Quote Link to comment Share on other sites More sharing options...
Wedge Posted October 9, 2007 Share Posted October 9, 2007 Funny , you got me stressed now ,my gauge goes almost to 90 when i go at WOT ! Quote Link to comment Share on other sites More sharing options...
Troutman Posted October 9, 2007 Author Share Posted October 9, 2007 Yes - been there, done that. I'm not trying to talk you out of it, just saying that it may not be the rear main seal. And I don't think it's practical to R&R the rear main bearing cap with the engine in the car. im really not tryin to pull the engine back out of the car..cause thats just going to lead to more money spent...(ie "now that the engine is out lets repaint the car like i talked about, and do this that and the other") hopefully when i drop the trans i'll be able to see whats going on and go from there. thanks for the info. Quote Link to comment Share on other sites More sharing options...
Troutman Posted October 9, 2007 Author Share Posted October 9, 2007 Funny , you got me stressed now ,my gauge goes almost to 90 when i go at WOT ! sorry.. i hate when people do that to me as well. so ill try and ease the situation by saying it could also be a faulty sending unit or gauge, so it could be reading incorrectly. Quote Link to comment Share on other sites More sharing options...
grumpyvette Posted October 9, 2007 Share Posted October 9, 2007 http://www.blackstone-labs.com/oil_viscosity.html http://www.bobistheoilguy.com/visc.html http://www.chris-longhurst.com/carbibles/engineoil_bible.html http://www.howstuffworks.com/question164.htm your REAR seals NOT usually under direct oil pressure,so oil pressure won,t dirrectly effect it. a good 10w30 oil meets those temp requirements Quote Link to comment Share on other sites More sharing options...
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