tyson Posted September 1, 2012 Share Posted September 1, 2012 (edited) So I'm baffled. I was out driving the Z this afternoon, nothing hard since it was afternoon traffic. Hit ~5psi briefly a couple times, nothing major or strenuous. All gauges were reading fine upon shutdown. (mechanical) Oil pressure at idle around 10psi, around 60psi at throttle. Car was running smooth. Tonight I went to go take the wife out for a drive. I started the car and waited for oil pressure to register (aftermarket mechanical gauge)...and waited...and waited. Nothing. It usually comes up around 5 seconds after startup, but I waited a good ~12 seconds. I popped the hood, noticed a little bit of oil on the valve cover under the breather. Checked the oil level, it was good. Opened the oil cap, cam was almost dry (just a very thin layer of oil from earlier in the day) Had the wife start it for a couple seconds, no oil on the cam. L28ET Engine is a rebuild with under 3,000 miles. Has oil cooler Just changed the oil~20 miles ago. Napa Synthetic 15w50 Fram PH8A filter Car sounds very smooth, not missing or anything. Anyone have any ideas? I've been around Zs for about 15 years and I've never heard of this. Edited September 1, 2012 by tyson Quote Link to comment Share on other sites More sharing options...
shri2222 Posted September 1, 2012 Share Posted September 1, 2012 Dump your fram filter, they are known to fail. Quote Link to comment Share on other sites More sharing options...
tyson Posted September 1, 2012 Author Share Posted September 1, 2012 Dump your fram filter, they are known to fail. I'll pull it in the morning and take a look at it. I've always heard of fram filters failing, but never seen or heard of one first hand. If the filter failed, could it completely occlude the oil flow? Quote Link to comment Share on other sites More sharing options...
shri2222 Posted September 1, 2012 Share Posted September 1, 2012 possibly, the oil goes from the pickup, to the pump, then to the oil filter before going to the head, so if the filter is collapsed it might cause the lack of oil in the head. Quote Link to comment Share on other sites More sharing options...
shri2222 Posted September 1, 2012 Share Posted September 1, 2012 possibly, the oil goes from the pickup, to the pump, then to the oil filter before going to the head, so if the filter is collapsed it might cause the lack of oil in the head. I'ed also double check your sender, if you have a aftermarket gauge/sender setup they often use a diaphragm which if bad will read no pressure. Quote Link to comment Share on other sites More sharing options...
(goldfish) Posted September 1, 2012 Share Posted September 1, 2012 Same thing pretty much happened to my old motor. Never figured it out. I would thing the oil filter bypass should open if the filter f-s up. Quote Link to comment Share on other sites More sharing options...
Zmanco Posted September 1, 2012 Share Posted September 1, 2012 (edited) I started the car and waited for oil pressure to register (aftermarket mechanical gauge)...and waited...and waited. Nothing. It usually comes up around 5 seconds after startup, but I waited a good ~12 seconds. I too have a mechanical oil pressure gauge on my L28et and the gauge begins to read pressure in about 1 full second (say "one thousand one" out loud). Perhaps you have a larger diameter hose between the gauge and engine which takes longer to compress and move the gauge? Otherwise, I'm not sure if that's a clue or not, but even 5 seconds seems too long compared to my setup. BTW, regardless if the Fram filter is the culprit, you might want to change to a better brand. There's a great writeup on the web by a guy who got curious about what's in filters so he cut them up and posted pictures. The Fram filters use the cheapest materials and are poorly made. Since I've seen those pictures, I've never bought another Fram oil filter, at least not their orange "extra guard". Edited September 1, 2012 by Zmanco Quote Link to comment Share on other sites More sharing options...
tyson Posted September 1, 2012 Author Share Posted September 1, 2012 Same thing pretty much happened to my old motor. Never figured it out. I would thing the oil filter bypass should open if the filter f-s up. Don't tell me that! I remember you fighting that for a long time. I too have a mechanical oil pressure gauge on my L28et and the gauge begins to read pressure in about 1 full second (say "one thousand one" out loud). Perhaps you have a larger diameter hose between the gauge and engine which takes longer to compress and move the gauge? Otherwise, I'm not sure if that's a clue or not, but even 5 seconds seems too long compared to my setup. I'm attributing it to having an oil cooler and running heavy weight oil and just taking a little while for it to pressurize the cooler? I'll change filters in a few minutes and report back. Quote Link to comment Share on other sites More sharing options...
Zmanco Posted September 1, 2012 Share Posted September 1, 2012 FYI, I have a 25 row oil cooler as well but run 10W30. I'm sure thinner oil makes a difference, but 1 sec vs. 5 makes me wonder if there's some other difference. Quote Link to comment Share on other sites More sharing options...
tyson Posted September 1, 2012 Author Share Posted September 1, 2012 Well I changed out the Fram to a NAPA and I have oil pressure again. I drained the filter into a screen and couldn't see any deformation or obstructions in it and there was no foreign matter in the screen. Looked up into the passages from the filter to the oil cooler block and it was clean and clear as well. I think I'm going to E-mail Fram as there is clearly something wrong with that filter. Again, I'm 100% positive that it's not the gauge, as I had no oil making it to the camshaft last night when I first noticed the problem. Regardless, I will never be purchasing another Fram again. Thankfully I'm religious about checking my gauges because I dodged a bullet on that one. Zmanco, I think I'm going to change to a thinner weight in a few days and see if that helps build pressure earlier. I should be OK leaving the current oil in the filter as long as it's the same brand oil correct? Thanks for your help everyone! Quote Link to comment Share on other sites More sharing options...
HowlerMonkey Posted September 1, 2012 Share Posted September 1, 2012 (edited) Careful with the thin oil like 10w-30. I recently fixed a volkswagen that someone had hydrolocked and filled the intercooler and intake piping with nearly 2 gallons of water. After running 3x oil changes that day of cheap castrol 20w-50 through it, the owner decided he wanted synthetic so he went and got some expensive 5w-30. The car was fine until you ran it hard enough to get some heat into the oil and immediately lit the low oil pressure light along with VVT hardware clacking. We let the car cool all day, restarted it and it was fine......until we got some heat into the oil again. I checked the owners manual and found that it specified 5w-40 oil and saw a footnote mentioning that 5w-30 was only to be used if you were adding 1qt or less to the recommended 5w-40 oil. We put the 5 quarts we had left of castrol 20w-50 and it's fine as it is already 83 degrees at 7:00 am and the car has over 100k miles. First time I had ever run into new oil that was too thin once warmed. I will not use any oil with a "30" at the end. I also went away from fram a long time ago and run purolator filters. Edited September 1, 2012 by HowlerMonkey Quote Link to comment Share on other sites More sharing options...
Oddmanout84 Posted September 1, 2012 Share Posted September 1, 2012 I used to like Fram. The orange and black looked pretty in the engine bay... Quote Link to comment Share on other sites More sharing options...
johnc Posted September 1, 2012 Share Posted September 1, 2012 The oil filter is after the pressure sender in the oiling system of the L6. A clogged oil filter will still read oil pressure. Also, the bypass valve in the block will open if the oil filter is clogged so oil will still flow to the main oil gallery. I suspect a sender or a gauge problem, not an issue with the oil filter. And Fram filters are fine, don't believe everything you read. Quote Link to comment Share on other sites More sharing options...
tyson Posted September 1, 2012 Author Share Posted September 1, 2012 The oil filter is after the pressure sender in the oiling system of the L6. A clogged oil filter will still read oil pressure. Also, the bypass valve in the block will open if the oil filter is clogged so oil will still flow to the main oil gallery. I suspect a sender or a gauge problem, not an issue with the oil filter. A Fram filters are fine, don't believe everything you read. Hmmm, but my head was dry when I was trying to diagnose it the night before. I had my wife start it for ~10 seconds while I looked at the cam through the oil cover and there was no oil on the lobe. Now I'm really confused. Quote Link to comment Share on other sites More sharing options...
johnc Posted September 1, 2012 Share Posted September 1, 2012 It could be the oil filter but I'm not convinced based on your description of the problem. Maybe the oil pressure was too low to trigger the filter bypass? You said you changed the oil and filter 20 miles before the problem occurred. Have you put 20 miles on the new NAPA filter? Generally a no oil pressure problem is the gauge/sender, the pickup, the pump, or the pump drive. But if you've got pressure back and are seeing oil on the cam lobe under the filler cap then those items are fine. Also, a 5W-30 synthetic oil is fine. I ran a 0W-30 synthetic in my racing 3L without any issues. Quote Link to comment Share on other sites More sharing options...
tyson Posted September 2, 2012 Author Share Posted September 2, 2012 It could be the oil filter but I'm not convinced based on your description of the problem. Maybe the oil pressure was too low to trigger the filter bypass? You said you changed the oil and filter 20 miles before the problem occurred. Have you put 20 miles on the new NAPA filter? Generally a no oil pressure problem is the gauge/sender, the pickup, the pump, or the pump drive. But if you've got pressure back and are seeing oil on the cam lobe under the filler cap then those items are fine. Also, a 5W-30 synthetic oil is fine. I ran a 0W-30 synthetic in my racing 3L without any issues. Put about 30 miles on the new filter, seems to be running perfectly fine again. Quote Link to comment Share on other sites More sharing options...
Sam280Z Posted September 2, 2012 Share Posted September 2, 2012 Years ago my ex-wife's mustang had an intermittent and random loss of oil pressure. Turned out to be a sometimes partially and sometimes completely clogged intake screen. I always push on the oil bypass valve when I change the filter to ensure that it is not stuck and will operate in the case of a clogged filter. Sam Quote Link to comment Share on other sites More sharing options...
Leon Posted September 4, 2012 Share Posted September 4, 2012 Careful with the thin oil like 10w-30. I recently fixed a volkswagen that someone had hydrolocked and filled the intercooler and intake piping with nearly 2 gallons of water. After running 3x oil changes that day of cheap castrol 20w-50 through it, the owner decided he wanted synthetic so he went and got some expensive 5w-30. The car was fine until you ran it hard enough to get some heat into the oil and immediately lit the low oil pressure light along with VVT hardware clacking. We let the car cool all day, restarted it and it was fine......until we got some heat into the oil again. I checked the owners manual and found that it specified 5w-40 oil and saw a footnote mentioning that 5w-30 was only to be used if you were adding 1qt or less to the recommended 5w-40 oil. We put the 5 quarts we had left of castrol 20w-50 and it's fine as it is already 83 degrees at 7:00 am and the car has over 100k miles. First time I had ever run into new oil that was too thin once warmed. I will not use any oil with a "30" at the end. I also went away from fram a long time ago and run purolator filters. Right, not sure if I follow that logic... Someone's VW didn't run correctly because he put the wrong viscosity oil in it, therefore you'll never use any xW-30 oil? Quote Link to comment Share on other sites More sharing options...
johnc Posted September 4, 2012 Share Posted September 4, 2012 Someone's VW that someone had hydrolocked and filled the intercooler and intake piping with nearly 2 gallons of water didn't run correctly because he put the wrong viscosity oil in it, therefore you'll never use any xW-30 oil? Fixed that for you... Quote Link to comment Share on other sites More sharing options...
Leon Posted September 4, 2012 Share Posted September 4, 2012 Fixed that for you... Good call. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.