Changing to a different oil.

[joseph szostek jr]

If you remember to change the oil filter too, you have my blessing.ha,ha,ha.sorry LOL

[JLWarren]

If you remember to change the oil filter too, you have my blessing.ha,ha,ha.sorry LOL

?? Everything I have previously posted assumes one is using a filter specifically made for synthetic oils. If you cut open the cans, there are some considerable differences between filters. The Amsoil filter's stated replacement interval is 12,500 miles, not 3000.
Based on oil analysis results using three different car types, (1984 Jeep Cherokee(2.5L), 2 different Dodge Grand Caravans(3.3L), and, of course, the PT) I have typically gotten this much mileage out of the filter before the analysis said to change it. The only time I've had a shorter interval was with the Cherokee and the PT, where, at the 20K-30K interval, the analysis indicated a shorter replacement period (only about 8,000 miles). I recycled the Cherokee in 2001, after getting the PT, because I simply didn't want the hassles of getting a new carburator for a 17-year old vehicle, and then getting it tuned up to meet CA smog requirements. (I had easily met CA limits up until 2001, even though I bought the Jeep in Idaho when I lived up there, but there was so much wear on the choke plate that it was drawing air in through the pivot pins from outside of the carb and messing up the mixture too much. It was literally rattling! I hated to do it, though, since I was still getting 28 mpg. When I was on long highway trips, I had gotten 33 mpg on four trips across country (ID/VA to RI/CA) with the Jeep.)
I have not yet installed the bypass oil filter system on the PT, but I plan to do so in the next couple of months. I just need to figure out where I can mount it. Based on my results with the bypass system on my old Cherokee, I should be able to extend the oil life out to 35-38000 miles. That makes the "higher cost" synthetic oil work out to about 1/2 the price of using the "cheaper cost" regular oil. The bypass filter typically needs to be changed every 18000 miles. The bypass filter mounting plate allows one to mount the two filters (bypass and regular) just about anywhere on the car you can run two hoses to (and have room for the filters. The bypass filter is about 4" in diameter and about 6-7" in length.) On my old Cherokee, I had them mounted between the grille and the radiator, so they got some significant cooling, up there, too.
What the bypass filter does that most regular filters won't do, besides the finer filtering (the bypass filter takes out particles above 0.5 microns. The regular filter takes out particles above 4 microns.) is remove water contamination (from condensation when cooling down, not coolant leaks!) This significantly reduces rust generation, and a host of chemical (acid) reactions as well, within the crankcase. Once the car reaches normal operating temperature, the water in the bypass becomes vaporized and is removed by the PCV system. And, since the bypass filter removes particles down to 0.5 microns, it takes a lot of the load off the regular filter, too. Once I figure out how to attach/implant pictures in this board's email, I'll post a picture with the installation, if anyone is interested, after I get it installed.
Jim Warren, 2001 LE

[Sci-Fi]

Interesting topic and replies. I do have some concerns after reading these posts (dual filtration testing starts toward the bottom):
http://theoildrop.server101.com/ubb/...6;t=000513;p=4
and opinions that adding a bypass filter may void your warranty.
A quote from BobTheOilGuy:
"A bypass filtration system is a design/ engineering change, not a direct replacement of the oem system. therefore the moss act would not apply and warr can be denied no matter what. I have seen toyota tell people that they must pull of the aftermarket bypass system if they want to maintain their warr. " "My advise, get it in writing so that approval is documented." And one more quote: "Ultimatly it's up to each dealer on warr approval but as pointed out, a mechanic might allow it,or a service writer, but, when it comes to higher ups getting involved, a great many car companies look for ways out and without written approval for such, you may or may not get it depending on your relationship with that dealer."
http://theoildrop.server101.com/ubb/...c;f=6;t=000898

Personally, ~$20 for an UOA is about the cost of 5 quarts of Mobil 1 and I would tend to opt for changing the oil and filter and request an UOA if I suspected an engine problem (coolent getting in the oil for example) or wanted a periodic analysis to keep a history. If I owned a big rig diesel that the fill is in gallons of oil, then UOA's would be a cheaper alternative. But to each their own and do what works for you.