1997 Toyota T100 Sr5 Oil Pressure Fluctuation

[Jjmarty]

Hey y'all I'm new to this thread, but aside from that please advise. I have a 97 t100 with bad oil pressure. Upon starting, the truck has good oil pressure around 40 psi and about 15 at idle, and while driving up unto approx. operating temps. At one point it will then increase with the throttle as usual, but at approx 2000 rpm, the oil pressure around 35 psi, it will snap down to 20 psi, and nearly nothing when brought back to idle. Do these have an oil filter bypass?? Please don't tell me my pressure regulator is bad by the oil pump. I need help bad no mechanic wants to touch it, going by the phrase : but the engines don't make trouble I never worked on one...

 

[kennythewelder]

Welcome to the forum. As for a bypass, there is one inside of the oil filter. All oil filters have one, but that is not your issue. IDK for sure what pressure they go into bypass, but it is a higher than 80 PSI I think. I would suspect the engine has sludge, but IDK for sure. You need to remove a valve cover, and see what it looks like in there. You will need to replace the gaskets when you do this. You can also try some Gunk motor flush and do an oil change. Its 5 minute motor flush, but the same product use to be 15 minute motor flush, so when I do mine, I run it for 15 minutes, but thats just me. You can also pull the oil dip stick, and see how it looks. If it is very black, and maybe a little thick, this can also be a sign of sludge, but to know for sure, you need to see inside the engine. Pulling a valve cover is a good easy way to do this.

 

[Glenn britton]

Hey jj,
T100 oil pressure fluctuation eh??
When I drove my 96 T off the showroom parking lot, I didn't make it two blocks down the street and turned around and went back. Back at the dealership I found my salesmen,and panicking, I said man this thing doesn't have any oil pressure whatsoever. Concerned, the salesman asked me to start it up, once I did he looked at the oil pressure gauge and ask what's the problem to which I replied it ain't got none. He asked me what I previously drove and I told him Fords, and I was used to 40~60 lb of oil pressure consistently.
He then asked me if I ever had any front or rear seal problems with my Ford and I told him well of course. He grinned at me and said, you can thank your 40 to 60 pounds of oil pressure.
He had told me Toyota figured out long ago that 16 lb of pressure is all that you need., So when the engine warms up and you think the oil pressure disappears,don't worry about it.
Well that was 22 years ago this June and 345000 Miles and change.
I've been using Valvoline 10w30 since I bought the puppy and she's as strong and powerful today as the day I drove it off the lot.
I just turned 62 not too many months ago and I believe this girl's going to outlast me. so enjoy your T, do your maintenance and take care of her, she' a hell of a ride and she'll return the courtesy.

 

[ncpapaul]

I bought my 1995 T100 3.4L in 2002, it had 95,000 miles and I got it cheap because the used dealer staff were all afraid of the low oil pressure. I had been driving Toyota trucks for years and didn't worry. It's 2018 now and I have 335,000 miles on it and it's still strong. It has oil pressure when it's cold (the high idle too) and when it warms up it looks like no oil pressure. I use Walmart Super Tech 5w-30 oil, a Motorcraft FL400S filter and a new air filter too, every 5000 miles. It is about 1/2 quart low at oil change and most of that is on my driveway parking spot from the oil drips. It will not retract the seat belts worth a darn and the darn plastic door handles with snap the little trip leg every now and then but it still cranks, runs and tows my trailers very nicely.

 

[Jjmarty]

Yea I wasn't worrying about it cuz everyone told me that. Put on a mechanical gauge and it started flat lining at idle and 5 psi max at any revs since I made the original post. So news update, the pump is out, new one is going in. But can anyone explain what the little ball is in the block/filter housing? Is that a check valve? And should it be so tight that I can't press it in? It is located in the pressure port.on the block side of the pump/ block seam. And also should I replace the water pump?

 

[Jjmarty]

Welcome to the forum. As for a bypass, there is one inside of the oil filter. All oil filters have one, but that is not your issue. IDK for sure what pressure they go into bypass, but it is a higher than 80 PSI I think. I would suspect the engine has sludge, but IDK for sure. You need to remove a valve cover, and see what it looks like in there. You will need to replace the gaskets when you do this. You can also try some Gunk motor flush and do an oil change. Its 5 minute motor flush, but the same product use to be 15 minute motor flush, so when I do mine, I run it for 15 minutes, but thats just me. You can also pull the oil dip stick, and see how it looks. If it is very black, and maybe a little thick, this can also be a sign of sludge, but to know for sure, you need to see inside the engine. Pulling a valve cover is a good easy way to do this.

Thanks, see my post below. What type of welder are you

 

[kennythewelder]

I worked offshore GOM for 32 years. Welded out there for 25 of those years, repairing and doing custom fab work to keep up with what was needed to keep an oil rig working. I have been working in town for 3 years now. Last 1.5 years at the oldest mechine shop in town. We do a lot of TIG work. We do Aluminum, steel, stainless steel, inconel, and monel. Also shortarc, and some stick welding. In addition to this, I - we also press bearings, so we do a lot of equptment repairs. I can and do weld it all. We only have 2 welders including me. A lot of it is build up work, to be mechined off. We also do fab work as well. You never know what is comming in the door next. Rite now we have a donut glazer for one of our local donut shops that we built from scratch, and there is a loading dock that was also built to load out 18 wheelers with fork lifts at a plant. This will be installed soon.

 

[Jjmarty]

Nice I bet the offshore paid well. I do mostly truck frame extensions and suspension from pick ups to rock trucks.new manufacturing consists mostly of pressure vessels primarily sand silos, brine tanks and piping for the gas well industry.

 

[kennythewelder]

Yes offshore was a good job. It pays about double what I make at home, but it is a young mans game. and I am starting to get old ( turning 59 very soon). Had throat cancer in 2012 (cancer free sence Jan 2013). My wife was after me to leave offshore for a long time. I worked 2 weeks, and came home for 2 weeks, for a lot of years. You miss a lot working like that, and I have worked a lot of holidays, even leaving to go offshore on Christmas day a few times.Then there is the danger of being out there and stuck on an oil rig miles in the GOM in the middle of no where. More helicopter flights, and crew boat rides than I can count. You do see a lot of wild life out there, and the water is crystal clear.Despite what people think, oil well drillers do not pollute the water at all. If they did, the government would shut them down. All of the rigs in the GOM are monitored by satellite. The second something goes wrong, big brother knows.