1HZ motor getting HOT

its been happening for a while now and once the temps get up over 36'c the old girl starts getting into the 3/4 on the temp guage.

tried modifying the thermostat and blocking the by pass hose but to no avail.

brand new radiator

so next alternative is to pull the viscos hub apart and fill with silicon or fix the fan permanently to the water pump.

something has to work to keep it half way

regards
oneday

Ray,

My old Ford Maverick (Nissan Patrol) used to do the same once it was working hard or the weather got hot. The issue with that motor - the 4.2 Nissan diesel - was that it was made to be put in a Japanese 5 tonne truck doing deliveries around towns in Japan. Consequently, the water channels in the block weren't big enough to get the cooling water through the block fast enough to keep the water temp down. A bigger rad woulda made no difference in that case. It may be the same with the 1HZ motor??

Other than that, you have a head gasket blown in a very minor way that doesn't show up until the engine is working real hard or it's stinking hot. My mate's old Mitsi was like that and when the motor finally croaked (snapped the crank!) the inspection revealed two minor head gasket blows.

On the other hand, my 6.5 Chevissan temp gauge doesn't move when towing over 2.5 tonnes, fully loaded in the back (no back seats at all!) at 140kmh (yeah I know that's illegal but sometimes I'm in a hurry). I often wonder if the temp sender is actually working!

My guess with a 1HZ - blown head gasket. It can do it without actually showing any signs in the rad or the sump or even using a lot of water, it's so small.

the sender unit is working coz when the temp gets up there the TX valve shuts down the air con to let the motor cool down a bit--added insurance I suppose..

may take the head of but we done that back when we sorted a piston issue out when I got the troopy.
new head gasket and planed the head, new injectors etc.

regards
oneday

Mind you, I must add that my truck has "well oversize" in it. It must be 5 row or more and it's all copper/brass, heavy as all buggery and it takes two guys to lift it out - or an engine crane like last time for soldered joint.

It's not an alum core and that could be the issue with your 1HZ. Alum cores are notorious for getting full of muck despite the best of anti-corrosion measures. It's just "something about aluminium" and your water is as hard as all get out up in KTA.

They don't call KTA the kidney stone capital of Australia fer nothing - as I well know!!!!

just put in a new radiator --copper old school.

regards
oneday

Ray didn't you replace the radiator not that long back ?

YEP ONLY DONE 2000ks

Going to pull the viscos hub apart and replace with silicon as a fix--has worked before on other vehicles.

regards
oneday

Ray,
You're probably on the money checking the viscus fan, the problem with those little "suckers" is they may be spinning when you lift the bonnet but not at the RPM they should be.
Have actually seen a aircon expert hold onto a fan with engine running, he let it go and it began to spin.
Rather than fluff around making them direct drive (bolt through the housing) or do what you plan, just flick a 8g nug over the counter and you have a new one doing what it is supposed to do.

At around 200000k. my 1hz was getting hot, particularly with a tail wind (FIIK!) so after a yarn or two with a mate or three went along to the local tojo mob for a tube of silicon. About as thick and same colour as honey.

Bought 2 tubes, around $20, pulled the unit apart (careful with the 0 ring) and put 1 tube in. It was then up to the lip level, re assembled and has never overheated since. (now 265000km)
The fan also spins free after warm up so assume the unit is working as it should.

Have been warned off those AM ebay assemblies, just a waste of good coin.
Mike

pulled the hub apart and looks like it had silicon in it but there was room for another tube and a half.

cleaned the faces and made sure the o ring was in the right position and bolted it together again.

will see how she goes next trip.

$13 a tube.

regards
oneday

Ray,

Have you got the radiator shroud on? That's the biggest contributor to engine overheating - other than a head gasket etc.

It's suspicious that the engine overheats when you have a tailwind. A fan is practically useless after a certain speed as the "speed generated air flow" is greater than the "fan generated air flow". Fans are only required when the truck is moving slow or in traffic.

Good luck anyway.

yeah Les everything is were it should be. Freshly painted shroud, 8 bladed fan, new radiator, new thermostat, tube and a half of silicon squeezed into the viscous hub.

when we put it all back together this arvo in the workshop it was blowing a shed load more air than befor we put the extra silicon in the hub, so hopefully we will go for a drive on the weekend to see if that was the trick we so desperately needed.

Mind u I am looking for a V8 troopy now.

regards
oneday

Hi Ray
Had the same prob with the old 80 before she met with the bovine bulbar rash. 2 tubes of silicone did the trick.
I think you will find it will run a heap cooler now.
Cheers
Phil

I don't know why they don't leave them a fixed item or make electric water pumps.

but will see on the weekend when we go for a ride again.

which reminds me if this works I also have a troopy that a mate also has with the same problem and is waiting to see how I go, then its in with his troopy for a silicone job as well

regards
oneday

My wife reckons I need a "silicone job" Ray. She reckons my tits are gonna start sagging soon!

I'm way past that Les--got a third tit growing out of my belly button.

regards
oneday