Definately NOT Normal

[Gauge]

Where I come from, high water temperature and low oil pressure is a sign of a very worn engine.

That is why the readings below from my oil pressure / water temperature gauge really surprised me, (sorry for the low resolution, but this was taken with a camera phone).

It just cannot be that my engine is worn out from neglect. I change the oil every 3K miles like clockwork and the guy I bought it from was a lawyer who did the same.

I used to think that low oil pressure at idle was normal and characteristic of these engines. A few weeks back, I did the water temp gauge mod posted by RavenTai, and thank God I did.

After doing the mod, I have come to see the low oil pressure from a totally different perspective. As oil heats it gets thinner. Now I realize that low oil pressure is NOT normal and it is caused by an overheating engine that I was never aware of because the temp gauge was modified by Toyota so I never saw the rise in temperature.

The picture below was taken at idle in 85 degree weather with the AC on after a long drive on Rt 295 in New Jersey.

After reading Landtank's post on the fan clutch, I think that may be my problem. I never remember hearing any roar at startup in my Land Cruiser like I do in my Tacoma.

I may order a new fan clutch today, as I am planning a 1,200 mile trip to Maine over the long holiday weekend and I do not want to drive it like this.

You know, after doing the water temp mod, I am CONVINCED that head gasket failure in these engines is a symptom, not a cause. The cause is a prone to failure clutch fan, further worsened by the fact that the idiot gauge Toyota installed would never tell you the engine was running hot and something might be wrong. Almost any vehicel with a cast iron block and an aluminum head will experience head gasket failure in constant 215 degree + temperatures.

 

[e9999]

so what does that temp reading correspond to, F wise?

Lessee, at 85 with AC on, and idling I'd probably be at 190F/195F for a while after a long drive.

My oil pressure never gets that low, but I'm running 15W-40. It tops up at the next to upper line when cold and never goes below the next to lower line.

 

[Texus]

gettin up there...

I bet It's pushin towards 225 F... atleast...

 

[Gauge]

RavenTai would have to confirm the temperature, but I belive he designed it so the gauge hits the red at the point where the AC cuts off automatically, which I believe is around 215 degrees. Way higher than I would ever like to run my engine.

I use 10W-30 regular oil, (which is what I was using when the picture was taken), but as of yesterday, I switched to Mobil 1 synthetic 10W-30. I will let you know if this makes it better or worse.

 

[e9999]

RavenTai would have to confirm the temperature, but I belive he designed it so the gauge hits the red at the point where the AC cuts off automatically, which I believe is around 215 degrees. Way higher than I would ever like to run my engine.

I use 10W-30 regular oil, (which is what I was using when the picture was taken), but as of yesterday, I switched to Mobil 1 synthetic 10W-30. I will let you know if this makes it better or worse.

a/c cuts off at 226F IIRC.

To me that would mean that the engine should be able to handle 226F for a while without ill effects.

 

[DuManchu]

I've never seen my oil pressure that low, but mine does go slightly below the "low" line in the middle while idling after it has warmed up. It usually stays smack dab in the middle or a little higher while driving after warming up.

My truck has 208,000 miles on it and I use 10W-30 dino oil.

 

[e9999]

why not go up a notch in viscosity in the summer -above 10W30- when it's that hot outside?

 

[fzj80kidpen]

Yeah, thats not right.
My oil pres never gets that low and my temp never that high.
If it was just temp I would suspect the radiator or cooling sys in general but with both oil and temp out of whack I suspect something deeper.
Water pump not working correctly?
Oil pump not working correctly?
Time for some pro's to weight in.

 

[semlin]

i believe ac cuts off at 216 and that is where the Raventai gauge is set to be at the bottom of the red. Do you use any oil?

I used to drop down well below the lower notch at idle after it was very warm. I changed from mobil 1 10w30 to a shell rotella ful syn 0w40 (only available in canada) and the problem was greatly reduced, so oil brand is a factor. However, then I did a valve grind while replacing my head gasket and since then the problem is completely gone. I am currently having very annoying hot operation issues just like you but it is not dragging my oil pressure down below the bottom hatch.

 

[cary]

That gauge shows the truck is running at about 215f. Since you said this is when idleing in traffic, the fan clutch is your first stop (if it heats up idleing and in slow traffic, fan clutch, if it gets hot the faster you drive, clogged radiator). Call CDAN ASAP and have him two day you a new fan clutch. You may also want to do a flush of the cooling system.

Your not going to like me, but dump the Mobil 1 10w-30. This is why I don't recommend it. It is forumulated on the thin end of the 30 weight scale and it is showing here with your low oil pressure at high temperatures. Drain and fill with Mobil 1 0w-40 or Shell Rotella 5w-40. In the event that you don't want to change all the oil, drain about 3 quarts and top back off with Mobil 1 15w-50.

 

[ashooter]

Dang... Now you got me worried. Is this temp gauge issue a problem with FJ's, or just FZJ's?

 

[Tools R Us]

Dang... Now you got me worried. Is this temp gauge issue a problem with FJ's, or just FZJ's?

Pretty much all brands factory gauges, for sure all Toyotas built in the last few decades work this way.

 

[cheap 40]

My oil pressure gauge has been that way since I bought mine. At that point on the factory gauge, my mechanical is reading about 40 psi. Is it possible that the factory gauge has failed recently, and you're just experiencing overheating? Just something else to ponder.

Tony

 

[gnx7]

My oil pressure when cruising at normal operating temps is at the 2nd to top bar. 134K miles.

Temp guage is always slightly under 1/2 way.

 

[landtank]

My guages looked exactly like that 2 weeks ago. RavenTai mentioned that the AC cuts out at 226* and turns back on at 217*. I was able to confirm that the needle half way on the red at the beginning is 217*.

You are just below that and the AC should have still been working.

At that point if you were to turn off your engine and check the fan it would have probably been very easy to spin and coasted some after being pushed.

At least that is how mine was.

 

[tarbe]

That pressure reading looks normal to me - for a truck that is on a 10cSt oil, is hot, hot, hot and running at 575 rpm.

 

[Pete483]

That looks like about the oil pressure I idle at, at least after one long block rebuild and another new head gasket.

My temperature started running high like that about 30k ago during a trip from MN to AL in which my PHH blew on a mountain pass in TN. How's you PHH?

 

[ashooter]

...A few weeks back, I did the water temp gauge mod posted by RavenTai, and thank God I did...

Can somebody post a link to this mod? I searched but couldn't find it.

thanks.

 

[Gauge]

Ashooter, attached below is the link to the Water Temperature Gauge Mod:

https://forum.ih8mud.com/showthread.php?t=64252&highlight=gauge

Just for the record, I want to state that I have always had low oil pressure at idle in the summer months especially when I use the AC a lot. In the winter time, my oil pressure was always higher at idle. However, winter or summer, AC or not, my "dummy" water temp gauge always stayed slightly below the middle - never showing any change in water temperature. It was always puzzling to me why the oil pressure would drop in the summer but the water temperature would remain the same. If the oil was thinning from heat, wouldn't the temperature gauge tell me that?

Bottom line is the water temp gauge was lying! Read the thread above and the problem with the "zener diode".

After the mod, I can see that the oil IS thinning because my temperatures are significantly higher in the summer with the AC on than in the winter.

In my case, I think my problem is a faulty clutch fan. But who knows how long the clutch fan has been bad and how long I have been unaware of it because the idiot temperature gauge never told me there was an overheating problem until I did this mod.

And you wonder why these engines are prone to head gasket failures?

 

[ashooter]

Ashooter, attached below is the link to the Water Temperature Gauge Mod:

https://forum.ih8mud.com/showthread.php?t=64252&highlight=gauge

...snip...

And you wonder why these engines are prone to head gasket failures?

My understanding is that it's the fZj's that have head gasket problems (not 91-92 FJ's), which is why I asked whether or not I have anything to worry about with my 92. I thought maybe the temp gauge was different with FZJ's.

Anyway, THANKS for the link Gauge! I will study up on it and see what I can see.