Overheating issue on 76' 1.1 Petrol

Hi Guys

Encountered my first issue that i'm at a lost cause with without spending some cash on a new rad/water pump to prove things out.

Can't say if it was running well before hand as it was sat in a outhouse for 10+ years, Decided to do a coolant flush to ensure it was all clean and free flowing.

What i've done so far;

Replaced one of the heater matrix hoses at back of the bay as previous owner had taped it up due to leak - found out the hard way.
Took Rad off, attached water hose to top of rad (hose end not cap) and cleared it all out - nothing come out other than clear water and left over coolant.
Took original thermostat out and thermo-switch for the fan and prove these out with boiling water pan trick, both ok.
Attached Rad back on, put thermo switch back in and attached bottom hose, ran water through top of rad again to clear out engine water, again clear and left over coolant.
Drained out, filled up with coolant/water from top hose again of rad untill trickled out of thermostat housing - put thermostat back in place and all hoses and filled rest through the cap.
started up with cap off and heaters on inside car, whilst squeezing all hoses bubbles come out as they should.
Temp gauge in car was at half way point and was slowly climbing, got to 3/4 and fan had not kicked in - before hand i proved out the fan and wiring by bridging the connections.
By this point the coolant was starting to boil over the cap so decided to turn off, let cool down slightly, re-fill and test again with cap on.
Temp gauge was high again after few minutes of running and fan had still not kicked in and the coolant was trickling through the cap pretty consistently.

I'd done this a few times around, before this and decided to change thermostat anyway as i had a new one lying around. still made no difference and it was definitely opening up when should be.

Don't know if anyone can shed some light or maybe had a similar issue?

Its the original rad in place, so my first thought was getting a new rad but id rather not if its all good!

Sorry for the long post, but i thought id try and get as much detail as possible for what i've done so far.

Its a top fill rad with expansion built into the side of it for reference, and also has the original black cap.

cheers in advance

Jack

 

Year and Model as there are differences in how the fan turns on.

I would ask if there is 12V on one side of the Fan switch.
As well as ask if you jumpered the fan directly to the battery.. to verify that the fan works at all.

Here is a how to flush and back flush your cooling system, as you need to flush it from the Radiator and from the engine.

How-to-flush-your radiator | Volkswagen Owners Club Forum

The reason I ask about year and model VW re-designed the circuit in the late 80's and 90's on the Cabriolet.  Where originally they have only a radiator fan switch.

So make sure that you have 12v on one side of the radiator switch, and that your fan is running, as a bad ground wire to the motor is the same as not having 12V to it as it is isolated from the frame.

Briano1234 said

Year and Model as there are differences in how the fan turns on.

I would ask if there is 12V on one side of the Fan switch.
As well as ask if you jumpered the fan directly to the battery.. to verify that the fan works at all.

Here is a how to flush and back flush your cooling system, as you need to flush it from the Radiator and from the engine.

How-to-flush-your radiator | Volkswagen Owners Club Forum

The reason I ask about year and model VW re-designed the circuit in the late 80's and 90's on the Cabriolet.  Where originally they have only a radiator fan switch.

So make sure that you have 12v on one side of the radiator switch, and that your fan is running, as a bad ground wire to the motor is the same as not having 12V to it as it is isolated from the frame.

Thanks for the reply, the year is in the title however it's a 1976, Golf L, tin top 3dr.
I linked out the fan by both coming off the battery to prove the fan and then joined the 12v which attaches to the switch and the ground which also attaches to the switch.

Ill take a look at the How to when I get a minute later on,  cheers.

Jack

If it was mine, I'd be taking the head off.

I don't know if this has the rubber seal that goes on the inlet manifold like the 1.8 has, but I think not. That's what caused issues with mine.

Worth doing a compression test first, just so you know what your in for.

Check the head for flatness, whip the valves out, decoke it, lap the valves back in, put it all together with new gaskets.

Sounds like you might not be to far from me. If you need to borrow any tools pm me.



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Longimanus said

If it was mine, I'd be taking the head off.

I don't know if this has the rubber seal that goes on the inlet manifold like the 1.8 has, but I think not. That's what caused issues with mine.

Worth doing a compression test first, just so you know what your in for.

Check the head for flatness, whip the valves out, decoke it, lap the valves back in, put it all together with new gaskets.

Sounds like you might not be to far from me. If you need to borrow any tools pm me.



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Appreciate the offer for the tools! however should have the everything needed cheers.

Yeah, i think the head will have to come off.
I was planning on buying a new Rad and fan as mine had seized up over the weekend after putting in a manual switch for it to see how it ran.

Ill do some research and find out what gaskets/bits i need to do an overhaul on it.

Thanks for the advise dude.

Top fill radiators are a nightmare to fill without getting an air lock.

I fill the radiator then remove the top radiator hose at the radiator end and pour the coolant into the engine till it's full and quickly put the hose on the radiator. Then burb the system by running with the cap off till warm.

Black radiator cap are also know to give problems, try changing it for a blue one.


Yours might be different as I've got the 1.6/1.8 engines.

Might be worth another try before taking the head off but you will need to get the fan to work 1st….

mark1gls said

Top fill radiators are a nightmare to fill without getting an air lock.

I fill the radiator then remove the top radiator hose at the radiator end and pour the coolant into the engine till it's full and quickly put the hose on the radiator. Then burb the system by running with the cap off till warm.

Black radiator cap are also know to give problems, try changing it for a blue one.


Yours might be different as I've got the 1.6/1.8 engines.

Might be worth another try before taking the head off but you will need to get the fan to work 1st….

You don't get the air bubble from hades if you drill a 1/8 to 1/16 hole in the lip of the t-stat.  But always fill it from both directions using the upper hose and the cap off the expansion jug.

I'll be ordering a new rad and fan today, along with the newer blue cap as they're only a few quid.

The filling up technique is what i used with the other rad and was still having issues, hoping this new rad solves it.

I might as well give the thermostat hole a go as i've got a spare, cant make it any worse!

Thanks guys, appreciate the insights.

Jack

Quick update, managed to sort it but forgot about this thread.

Replaced the Rad along with the newer cap, issue was still there.
Decided to put in a manual override switch for the new fan i put in place as the other seized and it seemed to have done the trick.

Sits at around 3/4 on the gauge or just under comfortably.

Looks like a lower temp Thermoswitch for the fan is needed. Jack
 

Winspaa said

Quick update, managed to sort it but forgot about this thread.

Replaced the Rad along with the newer cap, issue was still there.
Decided to put in a manual override switch for the new fan i put in place as the other seized and it seemed to have done the trick.

Sits at around 3/4 on the gauge or just under comfortably.

Looks like a lower temp Thermoswitch for the fan is needed. Jack
 

I had the same problem with the thermo switch recently and as these small block engines have very little coolant anyway they use the fan a lot. Mine came from my local motor parts supplier there readily available and cheap www.mpdonline.co.uk
01362 700500. Fixed the car straight away.