Considering purchasing a 94 Formula with 28k on the odometer. Car looks to be in great shape, but the hot idle pressure concerns me. It holds right at 20#'s. My 89 Formula with >100k holds just under 30 at hot idle with 10w-40 dino oil.

Would 20#'s be normal if there was 5w-30 synthetic in there? Car is at a wholesaler, so no use in asking them what was used.

Thanks.

 

I would say that is better than average. Lots of people with lower hot idle than that.

 

That does sound a little low. It may also not be accurate. The gauge or sender may be off accuracy. It would be nice to be able to stick a real gauge on there for a check. Sounds nice with such low milage if the price is right. Later>>>>>>>

 

I'd say 20 is the average for an LT1 at hot idle with the oil pump in good shape, actually, for the stock oil pump at least. I think the specs say a min of 6 psi for every 1k rpms, so it certainly won't hurt the engine at all.

 

Sounds about right to me, but at only 18k, that does seem a tad low though. It's enough, but replace that sending unit or hook up a mechanical guage up to see. 2 guys I know with LT1's(94, 95) run just below 40 hot cruise, 18ish idle and both have close to 100k. Another ran 25ish, 45 cruise, 55+ WOT on a 97 Z with 90k. I'm not sure, I guess some of guages on the older cars might read lower than the newer ones.




Jason

 

Thanks for the replies.

 

I get ~60 cold idle, 18-24 hot idle. Mobil 10-30 synthetic on a 140k LT1

 

i think with that mileage it is kinda low. i run 20-25 hot and 40-50 cold. that is with 125,000 miles and a big cam. but also using 10w30 oil. eh

 

I haven't heard of any that are the "same". When I first got mine I questioned the service manager & he called a tech wrench. The wrench explained to me that the LT1 has a hi volume oil pump , not a high pressure. I personally think that the low pressure readings at idge are scary. The owners manuel states that if the idle pressure drops below 20 lb. to contact the dealer.

Mine hot in the summer will go to 20, then 18, then pop, back to 20. This is with Mobil 1 10-30, 160 stat, & reprogramed computer.

 

Mine reads about 10 or so PS1 which is actually common for a lot of people. The pressure jumps about 6-8 PSI per 1k RPM and I get about 50-55 PSI at WOT. That is at hot idle with 5w-30 Valvoline Durablend and 90k shortblock.

 

I've got just under 98k on my LT1 and the oil pressure is about 20psi hot (in drive) and about 40psi at 60mph. At full throttle it usually goes no higher than 50psi. I know my engine is in near perfect shape since it runs extremely well and my oil analysis results show very low wear numbers too.

 

Glad to hear that Patman. I just threw in my motor and thats exactly what I get on mine. I was beginning to think the advise that Nick gave me to change out the spring wasn't good.