oil pressure slow to build

[crewchief219]

I just hooked my mechanical gauge back up and verified that for some reason its taking 1-3 secs to build oil pressure. The engine starts fine, runs for a couple seconds with no oil pressure and then shoots up to 45-50 psi. Is this normal? If not what's causing it? Maaaan I hope its nothing..... please help.

 

[crewchief219]

A couple things to add.. I changed my oil cooler because the pressure regulator was stuck open. I had a manual gauge hooked up to see if my oil pressure problem *** fixed and it was. I never noticed a lag in oil pressure from starting, I only saw it when I hooked up my stock 'dummy' gauge back up. I thought maybe the pressure switch is old and lagging but wanted to make sure so I put the mechanical gauge back on and that's where I am now. The only other thing I've done was put two new batteries in and the truck starts much faster than it used to but that's about it. I use a motorcraft filter and motorcraft oil. It didn't seem to lag at all before, only after I put the stock pressure switch back on. Any advice on this would be appreciated.

 

[argve]

all of mine have lagged when first starting in the morning. Especially in the winter - this was even on fresh rebuilds. Which it should lag a little because the oil pump is mechanical so it's not pumping until the engine is turning over. As they age they will take a little longer to build pressure. Or also will take a little bit more if she needs an oil change.

 

[crewchief219]

That's good to here. Is it still normal for it to take a second or two when its warmed up and shut off for a less than a minute? Id be less concerned if it were always like this but it just seemed to happen overnight. I was getting oil pressure immediately. It got a bit cooler here but not real cold yet. I could change the oil but it would be way early.

 

[icanfixall]

When I used a mechanical gauge I found the same issue. Slow to build and very slow to drop. Felt I had a line plugged so went looking.. Nope, all the lines were clear but. This was copper tubing and when I cut it to fit the rolled the cut edge so much it closed off the tube. So I opened up the ends of all the cut tube and presto. I had fast oil pressure up and down once again. This same gauge was in the truck for years working fine. Then I modified it and had these issues.

 

[crewchief219]

Huh.. it would make sense that there was a crimp or blockage somewhere but I can't figure put what or why. I didn't modify anything but maybe some dirt fell in the hole when I swapped the gauges?

 

[dirtbiker]

When I first start mine up and it's cold out, it takes a few seconds to build up to 40 psi (I have a mechanical gauge). I let it build up to 40 before I tap the throttle to get the high idle going. Once it's warm, the gauge is very responsive, so I figure it just takes awhile to build at first because I'm still running 15w40 and it's thicker at cooler temperatures and as someone mentioned before that the oil pump is mechanical. I would trace your line and be sure it's not kinked off even slightly though, just to be sure.

 

[crewchief219]

That's something else worth mentioning.. its not as responsive to changes in throttle as it was when I had it hooked up the first time. Its the same gauge but its acting like a different truck. I'm sure you guys are on the right track. The lines not kinked though, I haven't routed it anywhere but out of the hood. And it was delayed with the normal electric gauge hooked too.

 

[racer30]

You need to remember that the oil system is not a closed system like a gasser....It has 8 .048 holes at the piston squirters...Over night you will have oil drain back to the pan to the level of the squirters. The system will take a few seconds to fill and come to pressure. My fresh build dose the some thing. No worries....

 

[chris142]

A 5w40 or even a 10w30 oil may/should pump faster than a 15w40 when cold.

 

[crewchief219]

Good to hear, thanks for all the input. It sounds like I'm really worrying over nothing.