mackrmodel686st Posted January 17 Share Posted January 17 Hello everyone, I'm looking for some opinions. I drive a 2001 cx613 with an e-7 427. Its the vmac engine with the unipumps. Very recently the oil pressure started to drop while at highway speeds. It usually runs about 40psi, (which I personally think is on the low side, but was told by a dealer that that is normal) but now is down around 20psi. Its about 10 to 15psi at idle, which it always was. The oil in the pan smells really burnt as well. The mechanics and I are thinking the motor is cooked. Its got around 1.6 million miles on it. The rods and mains were done probably 12 years ago or so. Again, just looking for opinions or confirmations. Thanks. Quote Link to comment https://www.bigmacktrucks.com/topic/73763-losing-oil-pressure/ Share on other sites More sharing options...
Joey Mack Posted January 17 Share Posted January 17 so in years past, we would roll rods and mains in and take the oil pump apart and look for scaring grooves inside ,and inspect the relief piston for scratches, and the spring. another thing to look at is the plugs on the end of the rocker shafts. they can loosen or even pop out. I say this, not knowing how good it runs and what color the exhaust is.. If the engine needs a re-build, (rings) then at least you will have the new rods and mains.. It has been a good way to get oil pressure back up. In most of the repair we did, the updated high pressure oil pump was installed.. Jojo Quote Link to comment https://www.bigmacktrucks.com/topic/73763-losing-oil-pressure/#findComment-545240 Share on other sites More sharing options...
mackrmodel686st Posted January 17 Author Share Posted January 17 35 minutes ago, Joey Mack said: so in years past, we would roll rods and mains in and take the oil pump apart and look for scaring grooves inside ,and inspect the relief piston for scratches, and the spring. another thing to look at is the plugs on the end of the rocker shafts. they can loosen or even pop out. I say this, not knowing how good it runs and what color the exhaust is.. If the engine needs a re-build, (rings) then at least you will have the new rods and mains.. It has been a good way to get oil pressure back up. In most of the repair we did, the updated high pressure oil pump was installed.. Jojo Exhaust is black, but doesn't roll huge amounts of coal. Only for a second or 2 when shifting or starting out from a stop. Seams to run fine, might be down on power a little bit, but that could be me never feeling like anything has enough power. It's never had pistons, rings or sleeves replaced either. Quote Link to comment https://www.bigmacktrucks.com/topic/73763-losing-oil-pressure/#findComment-545243 Share on other sites More sharing options...
Joey Mack Posted January 17 Share Posted January 17 Black smoke can be a boost leak.. can you pressure test the charge air cooler and intake manifold for leaks? I would do it just because.. Quote Link to comment https://www.bigmacktrucks.com/topic/73763-losing-oil-pressure/#findComment-545249 Share on other sites More sharing options...
Mark T Posted January 17 Share Posted January 17 Check the soft plugs didn't come out of the rocker shafts ? Quote Link to comment https://www.bigmacktrucks.com/topic/73763-losing-oil-pressure/#findComment-545250 Share on other sites More sharing options...
mackrmodel686st Posted January 17 Author Share Posted January 17 1 minute ago, Joey Mack said: Black smoke can be a boost leak.. can you pressure test the charge air cooler and intake manifold for leaks? I would do it just because.. Like I said, its not excessive smoke. And I don't see how a boost leak would cause low oil pressure unless the turbo was junk. I don't believe that to be the problem as it seams to have decent power. Again, I always feel like nothing ever has enough power. I know a guy with a 379 pete with a fresh overhaul on a c15 cat that rolls way more coal. I realize that's comparing apples to oranges, but my truck smokes about the same as it always has. Quote Link to comment https://www.bigmacktrucks.com/topic/73763-losing-oil-pressure/#findComment-545251 Share on other sites More sharing options...
Joey Mack Posted January 17 Share Posted January 17 boost loss is not related, I just put that in there because Im seeing 2 issues.. Quote Link to comment https://www.bigmacktrucks.com/topic/73763-losing-oil-pressure/#findComment-545253 Share on other sites More sharing options...
mackrmodel686st Posted January 17 Author Share Posted January 17 1 minute ago, Mark T said: Check the soft plugs didn't come out of the rocker shafts ? I can have the shop guys look at that. It's easy enough to pull the valve covers. Quote Link to comment https://www.bigmacktrucks.com/topic/73763-losing-oil-pressure/#findComment-545254 Share on other sites More sharing options...
Mark T Posted January 17 Share Posted January 17 Does the engine brake still work ? Quote Link to comment https://www.bigmacktrucks.com/topic/73763-losing-oil-pressure/#findComment-545255 Share on other sites More sharing options...
mackrmodel686st Posted January 17 Author Share Posted January 17 1 minute ago, Joey Mack said: boost loss is not related, I just put that in there because Im seeing 2 issues.. It did get a new air to air last year, and the boost hoses look good. I haven't noticed and strange whistles either. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/73763-losing-oil-pressure/#findComment-545256 Share on other sites More sharing options...
mackrmodel686st Posted January 17 Author Share Posted January 17 1 minute ago, Mark T said: Does the engine brake still work ? No, hasn't worked in at least 10 years. From what I've been told, it hasn't worked since the rod and main bearings were done years ago. 10 years is as long as I personally know the truck. Quote Link to comment https://www.bigmacktrucks.com/topic/73763-losing-oil-pressure/#findComment-545257 Share on other sites More sharing options...
Mark T Posted January 17 Share Posted January 17 Yikes. If the rocker shaft soft plugs are the issue, and for that long ? Safe bet everything on the overhead is galled up bad. You're gonna be looking under valve covers and likely taking the pan and pump off for a good inspection. Any chips or filings in the oil ? Basically what Joey already said. Quote Link to comment https://www.bigmacktrucks.com/topic/73763-losing-oil-pressure/#findComment-545258 Share on other sites More sharing options...
MACKS Posted January 18 Share Posted January 18 He states in his opening post the oil pressure jus recently started dropping,what I find interesting is that his idle oil pressure is still the same ,I’m thinking maybe a problem with the oil pump or relieve valve… 1 Quote Link to comment https://www.bigmacktrucks.com/topic/73763-losing-oil-pressure/#findComment-545262 Share on other sites More sharing options...
Joey Mack Posted January 18 Share Posted January 18 I have an oil pressure gauge on a 20' hose that I put in on the top of the centrimax filter housing. i have a 't' fitting on it so I can put the line and pressure sensor back in line, then I can hang it in the cab when I test drive.. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/73763-losing-oil-pressure/#findComment-545263 Share on other sites More sharing options...
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