1HZ runs hot, tried the usual stuff

[rockcrawler31]

Hey all.

I'm still having dramas with my lemon replacement motor. It's fine around town but as soon as it gets to some hills it gets pretty warm. I know that it should move a little up the ranges but even with foothills it gets up to two thirds and stays there for ages.

what i've done/checked so far

Radiator is new and flushed, gets warm all over so no blocks
thermostat is good
hoses good
doesn't collect any shite in the water filter i have
doesn't use any water
running the heater inside helps a bit (but sucks as a passenger)
doesn't seem to have any air locks
water pump is only 130k old (as is motor)
fuel pump was rebuilt 20k ago as was injectors
water colour test from radiator indicated no gas in water
no colour in oil

what next? what other tests can be done? anyone know how much i'm up for to get the fuel system checked? it doesn't seem to be blowing a lot of black smoke so i doubt it's over fueling

how do i check that the actual senders are accurate?

I've just put in a modified thermostat (i drilled 4 1/4"holes in it) to get some extra flow as an experiment, but it's not ideal because it won't get to running temp around town and i reckon it's a bandaid solution to the real problem

[Shadow]

get an aftermarket mechanical guage. Just a cheapoie will do to verify your semnder isnt crook.

[Toy80Diesel]

How about the fan clutch? (viscous)

Mine was playing up occasionally and I found this was the problem.

[Shadow]

How about the fan clutch? (viscous)

Mine was playing up occasionally and I found this was the problem.

the fan isnt doing dick at 100k


fan only helps airflow when your sub 60, probably even slower actually.

[Suspension Stuff]

Get a pyro metre a temperature sensor connected to the exhaust and monitor the temps. Then get someone to back the pump off a bit. It might be running a bit more fuel than it needs to causing heat. Also use 3rd gear where you would use fourth or 2rd instead of 3nd as they don't like being laboured.

Shane

[Top Cat]

Is this replacement motor the same as the original with the same bore etc?

Is this a new or reconditioned motor?

[rockcrawler31]

it's a second hand replacement motor. done 120k's

will try the pyro thing if all else fails. i have just bought an original toyota temp sender (70 bucks for a pissy little bit of brass!!! )to try and eliminate that as a fault

[ads80]

a stuffed injector can cause a diesel to overheat, try an injector cleaner this may work or you may need new injectors , have seen the exact same problem b4 in a 1hz and it was a stuffed injector, the cylinder heads are also a common problem they crack and this is hard to detect, good luck none of the above will b fun or cheap bit of luck the injector cleaner may work give it a good 200ks

[me3@neuralfibre.com]

How about the fan clutch? (viscous)

Mine was playing up occasionally and I found this was the problem.

the fan isnt doing dick at 100k


fan only helps airflow when your sub 60, probably even slower actually.

I had a 1KZTE Auto Surf that disagrees with your statement. Standard nudgebar, small lights. Bought 2 tubes of silicon from Toyota, presto - high RPM overheatig dissapeared. The clutch was locking when hot no worries, then slipping or unlocking at 3500RPM+. 120km/Hr or 20KM/Hr - overheat. And I tried a bigger landcruiser fan to help as well.
Add some silicon fan oil - worked wonders for me.

[Yumsylux]

a fan is there to help pull air through your radiator when your car is stationary or going slow without much air flow. At 100kms there is more air flowing through you radiator than a fan will ever pull through. It's common sense really.

[Shadow]

How about the fan clutch? (viscous)

Mine was playing up occasionally and I found this was the problem.

the fan isnt doing dick at 100k


fan only helps airflow when your sub 60, probably even slower actually.

I had a 1KZTE Auto Surf that disagrees with your statement. Standard nudgebar, small lights. Bought 2 tubes of silicon from Toyota, presto - high RPM overheatig dissapeared. The clutch was locking when hot no worries, then slipping or unlocking at 3500RPM+. 120km/Hr or 20KM/Hr - overheat. And I tried a bigger landcruiser fan to help as well.
Add some silicon fan oil - worked wonders for me.

At 120km/hr your fan is more of a hinderance than it is a help. This is year 8 science stuff.

[Beefcake]

I agree it could be the fan, put two tubes of the silicon in it which should just about lock it up full time. No harm in this, did it on mine when I turboed it and never had a drama.
As for a fan doing nothing at 100km/h, I see the logic that you would think it would hinder, but I've been in plenty of trucks where the Horton fan will kick in at 100km/h. They do this because the sender works off the water temp which is obviously getting hot and the fan soon cools it and it cuts out again.
Also who fitted the fuel pump? might pay to have the timing checked again. Won't cost much at all. Of course if it was getting hot before the pump was done doubt it will be that.
Good idea to try an independent gauge as suggested. This will eliminate your sender, wiring and gauge. Try putting your sender into boiling water too and see what the gauge reads like, at least you know the water is close to 100deg and you should be able to judge where the gauge should be.

[mule75]

I agree it could be the fan, put two tubes of the silicon in it which should just about lock it up full time. No harm in this, did it on mine when I turboed it and never had a drama.
As for a fan doing nothing at 100km/h, I see the logic that you would think it would hinder, but I've been in plenty of trucks where the Horton fan will kick in at 100km/h. They do this because the sender works off the water temp which is obviously getting hot and the fan soon cools it and it cuts out again.
Also who fitted the fuel pump? might pay to have the timing checked again. Won't cost much at all. Of course if it was getting hot before the pump was done doubt it will be that.
Good idea to try an independent gauge as suggested. This will eliminate your sender, wiring and gauge. Try putting your sender into boiling water too and see what the gauge reads like, at least you know the water is close to 100deg and you should be able to judge where the gauge should be.

DON'T make your viscous hub solid!!!!!!!!!!!!!!!!!!!!!!!!!!!!! i did this ages ago and it was fine untill i did a river crossing and the blades flexed while trying to push the water and put a massive slice right thru my radiator!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

[rockcrawler31]

Hi all. been away for a bit overhauling the front end

i've just put in a new sender and will test it tomorrow, the fan is well oiled as i have done that.

i will also run the injector cleaner and enquire as to the price of a timing check. thanks all for the responses

[Beefcake]

DON'T make your viscous hub solid!!!!!!!!!!!!!!!!!!!!!!!!!!!!! i did this ages ago and it was fine untill i did a river crossing and the blades flexed while trying to push the water and put a massive slice right thru my radiator!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Can't argue I suppose if it's happened to you. I never had that drama but.

[dow50r]

Cobber
There r a few ways to continue.
Its common for the fan thingy to loose its oil, replacement costs a bit, easiest way to check it is to fit an electric fan from an old vl commodore or similar in front of rad, and see if it fixes your problem...if it doesnt, u will have bonus ice cold air ...
Second thing is exhaust....undo the muffler flange and see if it still gets hot....common to drop a baffle...especially if you havnt got the flex joint in situ
Third is it actually getting that hot??? look at another diesel to see where the earth bolts to on the motor, sometimes a mising earth from the head will give a hot gauge when the motor is only warm....(beeen there done that)
Andrew