What happened?

So I put in a new radiator this weekend. That went smoothly, and since I was gettting close to oil change time, I figured I'd change it while I had it in the warm garage. So I change it with the usual Castrol 10W-30 and Purolator (the bigger one L30001) filter. Before the change I had 50 psi at highway speed and 30 psi at idle. Now I only have 30 psi at highway speed and 10 psi at idle. :scared: I'm thinking it must be the filter. Opinions? Opinions on what filter I should use besides Fram, (I have always had good luck with Purolators?)????

Well, all three of our jeeps run Mobil-1 oil, 10w30, and either mobil-1 or K&N filters, sometimes OEM Mopar. Filters can make a big difference in oil pressure especially when new and there is good flow thru them the pressure can be low. As they filter out stuff and start to plug up the pressure goes up till it reaches a certain point, at that point the bypass spring in the filter mounting boss assembly kicks in and the oil bypasses the filter completely.
The wifes Olds also runs Mobil-1 oil and either Mobil-1 filters or K&N, I was a bit put off by K&N a year + ago when they kept loosening up on my XJ but I tried them again and had no problem. Then last weekend I changed the wifes olds oil and the K&N was very loose. I was not happy, I don't know if K&N keeps changing the seal material or what but I don't like my filters to be that loose especially on the Olds where it is tough to check, have to crawl under and reacy up between the engine and radiator. Finally a local parts store has started carrying both K&N and Mobil filters so I've got 8 Mobil-1 filters on the shelf, 6 for the jeeps and 2 for the oldsmobile...

Filters can make a big difference in oil pressure especially when new and there is good flow thru them the pressure can be low. As they filter out stuff and start to plug up the pressure goes up till it reaches a certain point,

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But I used to have 50 psi on the highway even when they were new. And it has never idled at 10 psi. Thats why I'm thinking it must be a bad filter.

I've never heard of a bad filter personally. To me it sounds more like your oil pressure sensor kicked the bucket.

catyrpelius said:

I've never heard of a bad filter personally. To me it sounds more like your oil pressure sensor kicked the bucket.

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I guess it could have but it worked fine before the oil change thats what has me puzzeled. Guess I could hook up a regular gauge and find out. I just can't believe that my sender took a poop right at the same time as an oil chnage.

I run only Purolator filters and have never had a problem. I have to wonder why you feel a need to run a filter other than the one designated for your application. "Larger" isn't necessarily better if it has a lower pressure relief spring, or some other internal differences.

Just go buy the Purolator that's listed for your year XJ.

Eagle said:

I run only Purolator filters and have never had a problem. I have to wonder why you feel a need to run a filter other than the one designated for your application. "Larger" isn't necessarily better if it has a lower pressure relief spring, or some other internal differences.

Just go buy the Purolator that's listed for your year XJ.

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I guess I was looking to have more filter surface area. I believe many here have done this conversion. I ran the larger one before and never had this problem. Before this oil change I was running the exact same thing (Castrol and larger Purolator) and didn't have any problems.

Update: I just put a regular Purolator on, and now my pressure is fine. I can't figure out how I ran the larger filter before and it worked fine, but oh well as is well again 50 on the highway and 40 at idle. I think i'll take Eagles advice and run the regular one from now on.

In using frams in the past it seemed they would cross fit different stuff. toyota now the same as something also now fits ??? . maybe they changed it internally and you found out the hard way.

jeepguy97 said:

Update: I just put a regular Purolator on, and now my pressure is fine. I can't figure out how I ran the larger filter before and it worked fine, but oh well as is well again 50 on the highway and 40 at idle. I think i'll take Eagles advice and run the regular one from now on.

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Another thing to think about - using a larger filter increases the oil capacity - maybe with the larger filter you were actually running with the oil low?

Rob

Nope I increased capacity with the filter, it was full. I dunno, I am just glad its fixed now.