Oil Pressure drop - why?

Messages
211
Location
Mississauga, ON
I recently changed my oil to Amsoil 10W-30 from the S2K 0W-30 on my '01 Honda Prelude. I use the Amsoil SDF-20 oil filter. The car runs well, but the oil pressure keeps dropping from 71 psi to 61 psi at 77mph (125Kph), and then stays constant at 61 psi. Any ideas of why this would happen? It happens when the oil is fully warmed up, not as it's warming up (that would make sense). I'm not losing any oil, and the ONLY thing I did differently was overtighten the oil filter by quite a bit, because the Amsoil filter gasket is very tough and my oil leaks if I don't tighten it a lot.
 

MolaKule

Staff member
Messages
21,599
Location
Iowegia - USA
I wouldn't worry about it unless the OP drops to 15 psi at 75+ mph. I have seen filters go into pass or partial bypass and OP sensors get flaky once in awhile.
 
Messages
8,756
Location
RI
Oil pressure also changes with engine load, oil temp, oil filter condition.... More than likely it is an optimistic dash gauge or sender that spikes and than slowly drops. I never trust factory gauges anyway. Find a quality aftermarket gauge and compare. As long as your engine is operating at its required pressure, don't worry about it. Oil bypass valves operate more smoothly than a sudden 10psi drop.
 

Ferrari

Thread starter
Messages
211
Location
Mississauga, ON
Thanks for the replies. My shop manual states that the minimum oil pressure whould be 10 psi at idle (I get around 12 psi) and 50 psi at 3000 RPM (I get around 55 psi). Is it OK to run so close to the recommended minimum? About the filter, I'll try changing it with another Amsoil one, but dayum, it costs a lot of money!
 

MolaKule

Staff member
Messages
21,599
Location
Iowegia - USA
I dunno, I pay $8.00 per filter and that's cheaper than Mobil1's. I run the SDF 20 in my Nissan and have never noticed any OP fluctuations.
 

Ferrari

Thread starter
Messages
211
Location
Mississauga, ON
Here in Canada it's about CDN$15.50 after tax (dealer cost). Hmm, it doesn't seem too expensive after all! I bought 3 of them for $46.50, and that seemed like a lot. Maybe I'm too cheap...
 
Messages
17
Location
Morristown, NJ
quote:
Originally posted by Idrinkmotoroil: make sure you are using a stock Honda filter, other than that not much else to worry about at this point.
The stock filter is a FRAM oil filter OEM'ed by Honda... try the Fram X2. -Gerhard
 
Messages
373
Location
Port Colborne, ON
quote:
Originally posted by Gerhard:
quote:
Originally posted by Idrinkmotoroil: make sure you are using a stock Honda filter, other than that not much else to worry about at this point.
The stock filter is a FRAM oil filter OEM'ed by Honda... try the Fram X2. -Gerhard

uh no, X2's are overpriced BS
 

Ferrari

Thread starter
Messages
211
Location
Mississauga, ON
It was a defective oil filter! I put in another Amsoil SDF-20 and the oil pressure is OK now. If I were to switch filter brands, I'd go with a K&N. I don't trust Fram.
 
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