[Onderbroek]

I went to Parys this weekend, and took a dirt road to Venterskroon lots of bumps and uphills - when I arrived at venterskroon the engine was hot, and the water boiling, it also had a burn smell - but the temp gauge was in the middle - I let it cool down filled up the radiator again and it overheated again on my way to parys - I've tested the thermostat which seems to be working fine. Not sure what can cause it. I did put on 2 spotlights on the bull bar but I doubt they are causing the issues- any idea of what is going wrong?

[Bozy97]

What condition is the radiator in, are you running coolant or just water?

[Gwagensteve]

Really could be a heap of things.

Your front bar is quite close fitting to the bodywork. Adding lights (I assume they are inside the hoop of the bar) will block quite a lot of airflow when combined with the fit of the front bar. Sierras have never had heaps of headroom in the cooling system - I've seen the overheat from brand new (all standard)

I see you have driven into some deepish mud. How clean is the radiator? Again, with the fit of your front bar it's going to be very hard to get the radiator clean. Also, bear in mind that SJ80's have an aluminium radiator core. These are easy to damage with a high pressure hose if you're trying to blast the radiator clean.

so maybe it was the lights that made the difference on top of everything else that's going on with the car.

If the radiator is clean and it's not the lights or design of the bar work that's complicating the issue, then look at :


Thermostat
Viscous fan hub failure (I think SJ80's run a viscous fan)
Cap not holding pressure
crack in a hose, radiator etc

If the car has boiled and pushed coolant out, it's not unusual for the gauge to read in the middle or even low. Water temp gauges don't read air temperature, only liquid, so if there is a steam pocket around the gauge sender you won't see hot on the gauge.

Steve.

[Onderbroek]

Thanks guys, how do i test the Viscous fan hub, when the car was hot, and the engine idling i was able to stop it with my hand, and hold it - there was no real pressure coming from the fan to turn.

I tested the thermostat and it seems to be working fine.

I'll clean the radiator , and give it a flush, and remove the spots to see if it might have caused the overheating

[steve]

Gwagensteve wrote:

Cap not holding pressure

happened to me once when mine was overheating, I got a new cap and it was all good again.

[charlie]

try a new cap this has happened too me as well.

[Onderbroek]

]Will try a new radiator cap.

This is where I put my new spotlights on, think they could be a contributing factor?

[JrZook]

Onderbroek wrote:

Thanks guys, how do i test the Viscous fan hub, when the car was hot, and the engine idling i was able to stop it with my hand, and hold it - there was no real pressure coming from the fan to turn.

This does sound like a possible issue. You are game to try and grab that thing while its already spinning. With the engine hot it sold be quite a solid drive even at idle.

[Onderbroek]

Is this a coily waterpump?

[Onderbroek]

Took it in to have it tested for head gasket leak - luckily no leak found - radiator cap was the guilty party -

[Santos]

keep the old cap in the glovebox , it may not work properly but if you lose the other one on the trail it will plug her up to get home.

[Gwagensteve]

I've successfully (temporarily) repaired a cap with the plastic membrane from the inside of a Gatorade bottle lid.

Steve.

[Santos]

Gwagensteve wrote:

I've successfully (temporarily) repaired a cap with the plastic membrane from the inside of a Gatorade bottle lid.

Steve.

Gold

I keep 2 or 3 rad caps in the car as i have replaced a few radiators and they usually come with new ones.

[Onderbroek]

So ive replaced the thermostat, radiator cap,coolant and waterpump and did a decent flush but it still overheats.

I took off my spotlights to see if that might have caused the problem

[Dec]

[quote="Onderbroek"]Thanks guys, how do i test the Viscous fan hub, when the car was hot, and the engine idling i was able to stop it with my hand, and hold it - there was no real pressure coming from the fan to turn.

I had this issue with mine after i did my conversion. If you're able to get your hands on a g16a (vitara Carby) viscous fan hub i'd hope it will solve your problem as it did mine, there's no modification needed bolts straight on. Second to that you can try refill your current fan hub with clutch fan oil.


Cheers Dec

[Onderbroek]

spotlights was not the issue, did 20km of highway driving then it started boiling,

does the fan play a big role when driving at high speeds?

[cairns27]

I thought that when cruising on the highway the fan was not really doing anything.


bye

[Onderbroek]

I also understand it like that

[Gwagensteve]

Depends on the way the cooling system is running. It's very hard to push air through a radiator, much easier to pull it. If there's low pressure in front of some or most the radiator (quite possible with the bar design) and the fan is inoperative or running poorly, it'll still overheat.

[kenn]

By the amount of rust and crap on the new cap, I'd be taking it to a radiator specialist and getting the whole cooling system checked. My money's on a blocked core.

[droverdave]

Have you done a good flush of the radiator? It does not take much for an old radiator to drop in performance due too rust/gunk build up.

Best bet is to take the radiator out, put it upside down, fill it up with water while holding your hand over the top (now at the bottom) inlet, then let it all gush out. Do this a few times until no more brown rust comes out.....

If you do this and still having dramas, new radiator time, since you have replaced everything else....

[shandy92]

Droverdave- sorry but doing that with water is not going to make much difference, water alone wont remove rust. If your going to remove the rad you might as well get it done by a pro. They remove both top and bottom tanks and clean out everything that shouldnt be there. Should only cost roughly $150 to get it done and will restore the rad to almost new cooling efficiency.

[droverdave]

Have you done it? I have had success doing it.

Every time i have done it on an old radiator, i have to do at least 5 flushes before i get clean water coming out. So it cleans something out. Sure better to let a professional do it, but as a last ditch effort that costs nothing I see no harm in trying.

For $150 I would just buy a new radiator.

[shandy92]

I havent no, but i do at work on hd radiators and we have to use a chemical. If it works, awesome.

[Onderbroek]

Ive done the "take radiator out flish with water" and add "radiator flush and do a couple of heat cycles" but nothing has helped

I had a chat to one of the local radiator shops, and they also suggested i bring it in, and they remove the plastic top, and by some way or means they check every core - luckily the only charge around 380 ZAR which is about 38AUD.

so this will be my next step - hopefully this will sort it.

[Gwagensteve]

Shandy don't want to be a hater, but with an aluminium block and head and an aluminium radiator, how much "rust" can there be in the system? there's about 18" of steel pipe that's normally clean as a whistle inside and the water pump impeller. I can't think of anything else.

Of course it's possible the radiator is blocked or largely blocked - and I agree that the cap looks dirty considering there should be clean green coolant on it, but I'm still going to point the finger at the fan hub first.

Steve.

[Onderbroek]

The guy at the radiator shop said the red was a mixture of some sediment and radiator sealant

[Gwagensteve]

Hmmmm - radiator sealant or generic stop leak? Wonder if it's done a head gasket or the sealant has plugged things up?

Steve.

[shandy92]

Yeah i agree steve, i wasnt really focusing my point on rust (even tho i said rust) but general sediment. I agree and would be doing the fan hub first.

[Onderbroek]

Gwagensteve wrote:

Hmmmm - radiator sealant or generic stop leak? Wonder if it's done a head gasket or the sealant has plugged things up?

Steve.

Good point, can you test for that?

another option

i can get my hands on a g16a - CARB version for about AUD 450 - it comes out of a coily, the guy wants to install a 1.9 volkswagen diesel engine.

he said the g16b was rebuilt before he installed it in his coily - how hard is it to install the g16a and, what adaptor kits do i need?

just thinking before i spend all this time and work on the 1.3, i could just as well upgrade to some more cc's