Hey Frank (@elripster ) and/or anyone else with a suggestion or opinion -
At last night's B-n-T meeting you mentioned you had your bottom end rebuilt while getting the head done. Something I perhaps should have considered, but did not... One of the things I have noted since getting my head done (a year ago now...) and I didn't notice it until last September while driving up hwy 99 through central valley in 100+ degree heat is that my oil pressure is for all intents zero while running along at 70MPH and 3000RPM... First thing I did when I noticed this was mildly freak out, then pulled off the highway, turned off the engine and got a soda, letting the oil drain back into the pan; checked the oil level and it was fine and clean... So, it's not as though I was running without oil, which is a good thing... When I got to Fresno I decided to pop into a quick oil change shop and have them dump the oil that was in it (same oil the shop put in after doing the head with only a few hundred miles on it) and replace it. I had the shop put in a little heavier oil (10W30 synthetic-mix as I recall), to at least know I had fresh oil and a new filter. On departing the shop yeah the pressure was better, but basically less hot, but it was nothing to write home about; and with a few minutes / miles it was back to reading near zero again which again gave me an uneasy feeling as I neared the long steep grade up to Shaver lake. Nevertheless the truck ran fine throughout the trip up and down and around the mountains and ever since; so maybe this is much ado about nothing...
In my old '95 80 the oil pressure was always around 1/3 scale on the dashboard idiot gauge, pretty much the same on this '97 until recently.
Now, when the engine is cold the pressure is up in the middle of the gauge, but once warm it drops to near zero. I have since verified this with an old school manual pressure gauge by installing a T at the engine block then cleaning the electrical contacts on the factory gauge sensor and its connectors (just in case they were dirty and part of the problem - they weren't). The mechanical pressure gauge basically agreed with dash gauge and read on the order of 30+ PSI when the engine and oil is cold, but drops to near zero, like well 1-2 PSI when hot, especially at low RPM (like when idling).
This really seems like a not good thing to me; however, when reading countless threads on Mud and elsewhere on the interweb everyone says meh don't worry about it, it's fine, mine's been doing that for the last 100K miles, etc, etc. Nevertheless, low oil pressure concerns me, especially when stressing the engine at high RPMs, low gears, during extended slow steep climbs.
So, my question is, what to do about this? Is it worth embarking on a crusade to service or replace the oil pump? Maybe run with heavier oil in the future (which may or not improve actual lubrication regardless of perhaps making the gauge read higher... And perhaps further degrading already poor MPG?
When you had your bottom end done Frank, did you service the oil pump? If so, is your pressure good when hot?
One thing I did have done when doing my head, and while the exhaust manifold was off, was have the shop remove the oil cooler (and really who places an oil "cooler" right next to the friggin exhaust manifold? I mean really Toyota?) and steam clean the cooler innards before reinstalling it with a new gasket. Could cleaning any gunk out of the oil cooler cause the pressure to drop?
Could anything else the shop did have adversely affected the oil pressure?
Inquiring minds, want to know!
At last night's B-n-T meeting you mentioned you had your bottom end rebuilt while getting the head done. Something I perhaps should have considered, but did not... One of the things I have noted since getting my head done (a year ago now...) and I didn't notice it until last September while driving up hwy 99 through central valley in 100+ degree heat is that my oil pressure is for all intents zero while running along at 70MPH and 3000RPM... First thing I did when I noticed this was mildly freak out, then pulled off the highway, turned off the engine and got a soda, letting the oil drain back into the pan; checked the oil level and it was fine and clean... So, it's not as though I was running without oil, which is a good thing... When I got to Fresno I decided to pop into a quick oil change shop and have them dump the oil that was in it (same oil the shop put in after doing the head with only a few hundred miles on it) and replace it. I had the shop put in a little heavier oil (10W30 synthetic-mix as I recall), to at least know I had fresh oil and a new filter. On departing the shop yeah the pressure was better, but basically less hot, but it was nothing to write home about; and with a few minutes / miles it was back to reading near zero again which again gave me an uneasy feeling as I neared the long steep grade up to Shaver lake. Nevertheless the truck ran fine throughout the trip up and down and around the mountains and ever since; so maybe this is much ado about nothing...
In my old '95 80 the oil pressure was always around 1/3 scale on the dashboard idiot gauge, pretty much the same on this '97 until recently.
Now, when the engine is cold the pressure is up in the middle of the gauge, but once warm it drops to near zero. I have since verified this with an old school manual pressure gauge by installing a T at the engine block then cleaning the electrical contacts on the factory gauge sensor and its connectors (just in case they were dirty and part of the problem - they weren't). The mechanical pressure gauge basically agreed with dash gauge and read on the order of 30+ PSI when the engine and oil is cold, but drops to near zero, like well 1-2 PSI when hot, especially at low RPM (like when idling).
This really seems like a not good thing to me; however, when reading countless threads on Mud and elsewhere on the interweb everyone says meh don't worry about it, it's fine, mine's been doing that for the last 100K miles, etc, etc. Nevertheless, low oil pressure concerns me, especially when stressing the engine at high RPMs, low gears, during extended slow steep climbs.
So, my question is, what to do about this? Is it worth embarking on a crusade to service or replace the oil pump? Maybe run with heavier oil in the future (which may or not improve actual lubrication regardless of perhaps making the gauge read higher... And perhaps further degrading already poor MPG?
When you had your bottom end done Frank, did you service the oil pump? If so, is your pressure good when hot?
One thing I did have done when doing my head, and while the exhaust manifold was off, was have the shop remove the oil cooler (and really who places an oil "cooler" right next to the friggin exhaust manifold? I mean really Toyota?) and steam clean the cooler innards before reinstalling it with a new gasket. Could cleaning any gunk out of the oil cooler cause the pressure to drop?
Could anything else the shop did have adversely affected the oil pressure?
Inquiring minds, want to know!
