Thread: Compression test results 1998 3.9ltr should I be worried ?

No .
But I don't like 6 much.
The rest are fine.
How old is the radiator? LR radiators have fine tubes that block easily.Flushing does not work, and usually you will need a new core if you have it rodded as long term blockages corrode the tubes.
Next to look at is viscous fan if the overheating is at slow speeds.
Next may be a partially opening thermostat, and this is a easy one as only costs $20.
If you do all that and still have a problem it is time to look at head gaskets, slipped sleeves etc, but be methodical and my bet is a blocked radiator.
Regard sPhilip A

If you used one of the push in readers thats not too bad you need to do a leak down test on pots 8,6,4,1 oh hell do the lot.

did you get the same number of cranks on each one and did each pot receive exactly the same amount of oil for the wet test?

if you used a proper screw in tester and gave each one the same number of hits then (and assuming that they all come up a bit closer on a retest) thats a bout average and what Id expect near the 250K km mark of reasonable driving.

Thanks Philip ,

Number 6 is a worry but I think its worth keeping the car and working on it a bit.
The plan is to change the thermostat and pull the radiator and have it cleaned . Hopefully this will sort it out a bit . Don't know how to check the fan clutch it has good resistance when cold , can you drain and change the fluid in them ?
The strange thing is it was getting warm in traffic but yesterday when I filled with premium 98 octane fuel ( have been using 91octane ) it started overheating straight away and had to blast the heaters to cool it down.
I'll see what happens with the radiator cleaned and thermostat.

Thanks
Matt

I'll see what happens with the radiator cleaned and thermostat.

"cleaned" and "rodded" are sometimes not the same thing. Cleaned can mean backflushing while rodded means taking the tanks off and pushing rods down the cores. This usually costs around $150 but is the ONLY way to to check a LR radiator and often results in the need for a new radiator becoming evident. Make sure that the radiator is rodded. Price above is you pulling the rad and taking it to a shop. It is not hard.

.

Don't know how to check the fan clutch it has good resistance when cold , can you drain and change the fluid in them ?

No you cannot, well you can and Toyota sells the fluid but it would mean drilling hole and I don't know where that goes.
A good indication of whether the viscous is stuffed is to look at the outside. Is it covered in fluid which is coming from the front or rear seal or is it dirty but dry. When the temp gauge goes over half/3/4 does the fan roar and you feel a drop in power? It is quite noticable.
They also usually roar for say 1/2 to 1 Km when starting from cold in the morning. My new 300Tdi coupling ( on my V belt V8-the coupling is a mirror image of the serpentine V8 one) goes on for more than 1KM.

Even with only a bit of fluid , it will pool in the bottom and be stiff when cold .
IMHO a rad rod, new thermostat and new viscous will fix it. If not you have bigger problems
Regards Philip A