Overheating 1985 1.9ltr petrol

[Azzman1000]

Hi all,

First post since the move from the old forum. I'm having some issues with my cooling system at the moment. I can literally drive all day and the engine temp stays with the needle around the center point, fluctuating either side of the warning bulb.

But as soon as I spend a little time stationary in traffic or in a busy drive through it starts heating up quickly and the rad fans haven't been kicking in. I've seen the temp gauge get to just over 3/4 and the water temp warning light flashes and still no rad fans. I held out a while with it running and watched the temp needle for as long as I was comfortable doing in hope they might kick in because they've always done so about the 3/4 mark anyway. My refill bottle and expansion tank started to boil over and I lost a bit of coolant in the gutterand quickly shut her down.

After this a noticed a bit of brown "gunk" on the inside of the expansion tank cap but the coolant itself looked clean. I've removed both heads and done gaskets in the last couple of years, I'm a novice mechanic and did it with help from this forum and from YouTube etc. I'm confident I've done it all correctly but I made the mistake of not flushing the cooling system (it was obviously empty), I just filled it up and bled it and off I went ant I've done a few thousand k's since so my brain tells me maybe that's left over gunk/rust and a few good flushes are a must.

Given that the temps are good while driving I assume the coolant is circulating properly and the rad is doing its job when it has airflow so its only that the fan isn't working that causing the overheat. I've jumped the connectors and the fan operates at both speeds so I'm thinking its the cooling fan switch on the radiator that is faulty ??

Before getting my van I had never really worked on cars/engines before so I'm not an overly mechanically minder person, I'm learning as I go so I apologize if I'm a bit ignorant. 
Am I missing something ? or does this sound like I'm on the right path ?

Thanks!

[Barry]

That sounds like you are on the right path. 

Out of stock at JK but available OS

https://brickwerks.co.uk/product/resisto...wbx-85-on/

Could always wire up a manual switch in the mean time. 

Sounds like it needs a good flush as well

[luckyphil]

Try Mick Motors for the Fan Switch

[Azzman1000]

That sounds like you are on the right path. 

Out of stock at JK but available OS

https://brickwerks.co.uk/product/resisto...wbx-85-on/

Could always wire up a manual switch in the mean time. 

Sounds like it needs a good flush as well

Thanks Barry, 
I'll look around and source one somewhere but I will definitely look at wiring up a toggle switch in the cab while I wait.

Cheers.

[Grantus]

Thanks Barry, 
I'll look around and source one somewhere but I will definitely look at wiring up a toggle switch in the cab while I wait.

Cheers.

Pretty sure that’s what Gazman did during a Perth summer a few years back, until I salvaged the 3 pin plug unit from a replaced radiator here I was about to dispose of, and express posted it to him.

Unfortunately, I no longer have one to send…

[Azzman1000]

This would be the one wouldn't it ?

https://www.justkampers.com.au/catalog/p...ew/id/161/

In stock!

[Grantus]

This would be the one wouldn't it ?

https://www.justkampers.com.au/catalog/p...ew/id/161/

In stock!

I thought this one was for the 1.9….

https://www.justkampers.com.au/catalog/p...1979-1984/

But the website is a little confusing - “suits 79 to 84”. 

Best to check if the one in the your bus currently matches either of them.

[Azzman1000]

I thought this one was for the 1.9….

https://www.justkampers.com.au/catalog/p...1979-1984/

But the website is a little confusing - “suits 79 to 84”. 

Best to check if the one in the your bus currently matches either of them.

mmmm  honestly it's kinda hard to differentiate between them on JK, but if I copy the OEM part number from JK and search for it on Heritage Parts which I've used regularly, the one they have in the picture has the exact notches in the plastic (3 in total) as the one in my van.

https://www.heritagepartscentre.com/au/2...minal.html

That said though, the other end the plugs into the switch only has the single notch and would most likely fit either assuming they are the same size.

[Oldman]

If there’s any confusion with JK, just call and speak to Kai…..his product knowledge is second to none.

[Azzman1000]

Update…

New thermostat and radiator fan switch are in. The old thermostat was definitely stuck closed, a kettle poured into a bowl wasn’t opening it but it would open a few mm at basically boiling if I put the pot on the stove. The rad now warms up and the temp feels even across the cores, the fan also kicks in as it should.

That said, the problem isn’t over. It looks like the suggestion of combustion gasses in the coolant could be correct. The system bleeds well and keeps it cool at first but after some driving the expansion tank can no longer fill to the top with coolant as room is taken up by pressurised air (hisses when removing the cap even with a cold engine). I’ve also seen some bubbling in the refill bottle ?
So I guess off come the heads, but I’m going to run a compression test first, just waiting on the test kit I ordered to arrive.

Unfortunately there is something else I need to diagnose. I started noticing a strange sort of grinding noise when coming off throttle. I’ll attach a YouTube link for the sound.
It’s been suggested elsewhere that this is bad valve adjustment making this sound which is an easy fix but I find it odd that it just started suddenly 

https://youtube.com/shorts/qyLXy5ZNFaQ?feature=share