Overheating - 1983 GX

Hi guys,

I'm new here as I've only had my golf for a week.

Other than the long drive home along the motorway I've hardly used her but I've been out to the shops today and come across an overheating problem.

As you expect, if pottering about things seem ok with the needle around half way on the temp gauge (doing 50mph brings the needle just under half way).
I got stuck at a train crossing so was sat a while and I noticed some steam coming from the bonnet where the expansion tank is located and the temp gauge was maybe 2mm over half way (no light on, but it works).

I got home just fine and let her run whilst sat on the drive as I wanted to see if the rad fan was working, it was and it brought the temp down whilst idling.

Any ideas what could have caused the overheating?

Coolant levels and the colour is good but I can't say how long it's been since it was changed.

All help appreciated

What colour is the coolant? If it's blue then it's meant to be changed every 2 years.

Old coolant wont make the car over heat it's probably something like a sticky thermostat, I would get a new thermostat and you will need to replace the coolant anyway when you remove the thermostat.

Not sure what size engine you have in the GX but if a big block 1.5, 1.6, 1.8 then this thermostat.

https://www.eurocarparts.com/ecp/c/Volkswagen_Golf+Cabriolet_1.8_1989/p/car-parts/cooling/car-cooling-parts-and-car-heating/car-thermostat/?209440040&1&c01e4844afd3a7f2e3f03130e2053c29a40e4e54&000325

Blue coolant and its ready mixed, 5l is plenty.
https://www.eurocarparts.com/ecp/c/Volkswagen_Golf+Cabriolet_1.8_1989/p/car-accessories/engine-oils-and-car-fluids/antifreeze-and-screenwash/blue-antifreeze/?523770501&0&cc5_865

Sale on this bank holiday weekend so don't forget to use the discount code and if collecting from a local store use click and collect to get discount as you don't always get it when walking up to the counter.

Blue coolant will be fine for small block cars, 1.1 or 1.3 but check the thermostat as I'm not up on those engines…

 

I recently reserved 5L of the Triple QX Blue from Euro car parts.  The discount didn't apply BUT it's only £7.99 off the shelf in the shop which is just a little more than half the price listed on their site.  Good thing I'd seen it or I'd have paid £14.49 for it!

Yes you have to get it at the right time at Euro car parts, no a lot of discount on coolant, works out £14.20 at the moment but probably cheaper than ready mixed stuff from Halfords?

Another thought over cooling…

Airlock in coolant system? Do you have an expansion tank or top fill radiator?

Radiator Caps do go bad.
Expansion tanks can leak.
I would say flush and back flush the cooling system, then replace the t-stat.  Drill a 1/8 to 1/16 hole in the lip of it and you won't have to worry about a bubble in the system.

Check the radiator core on the inside of the fan shroud to verify that you don't have a seam leak on the radiator matrix.  I just found one on mine, and the radiator is only about 12 years old.

Check the condition of your hoses and if you are using the old green type of coolant then you can use a UV light to verify that all is well as the Green stuff glows under uv, and I have found many a water pump leak that way.

From the sounds of it your car didnt actually overheat.
If it had you'd of dumped most coolant on the road and needle gone to max.

Mine did it on the MOT tester but I had a fan issue

If your fan is working then it can't overheat but I would suggest your expansion tank cap is knackered, you'd be surprised how much coolant you can lose out of one thats had enough.

I had the same thing on my last proper drive on Sept 30th last year

Oh and definitely look up Briano coolant flushing methods.

I got my coolant system from brown to crystal clear before I finally filled with coolant again

Guys your all legends!!!

I have two spare new expansion tanks for some reason so I will swap one out next week.

I'm also thinking I will just give the coolant system a good service and do the T-Stat and flush, I have a week off from the 13th so it will keep me entertained lol.

Thanks everyone!!

The links to all my How I did thats are in my signature, but I will let you see the direct link, be warned I have a LHS and Power Steering on my Cabriolet but it is the same for the basic Golf for the 81 diesel that I drove for 20 years.

I will tell you that cleaning the t-stat bolts is a good thing, coating them with never-seize before going back is also a must.  But the biggest hint is to use a torque wrench when finally replacing the t-stat cover and if yours is Plastic get a new one….use a torque wrench to put the 87 in/lbs of torque on the bolts, as they are steel bolts going into aluminium and strip very easy with over torqueing.

https://volkswagenownersclub.com/vw/showthread.php/21399-How-to-flush-your-radiator


 

sounds very complex did it over heat
did it not over heat surely coolant is
just water  the stat surely is not going
to fix its self  probably be opening temp
around 88 degrees c so half way on the
gauge would be no where that temp.

I also forgot that if you don't have the upper radiator card (between the front valance over the top of the radiator and into the fan shroud) you can lose a lot of cooling efficiency at stop as it prevents engine compartment are from being sucked in and over the radiator matrix as a  preheated air…making your coolant hotter and fooling the engine temp senders…

At Idle the heated engine compartment air collects at the top of the bonnet.  When your fan comes on, it is pulled through the opening of the uncarded radiator, and over the Matrix Heating up and not really cooling the fluid.

See this thread on Engine Compartment temps.
Debunking the Cold Air Intake myth | VW Vortex - Volkswagen Forum

Also on a functional system you will see that when the radiator fan is running it draws the rubber mats in to the shroud closing them, to redirect the air through the shroud if the upper card is off it will not shut them completely…when you are driving, they are forced open to allow total cool air over the whole matrix.

Yes I smoke tested the airflow in the engine compartment with a Halloween smoke machine and my bore scope camera one after noon years ago….with a upper card installed and one missing (YES I WAS BORED.).

No upper card on a new to me car.



After Brianizing

 

nicci21paul said

sounds very complex did it over heat
did it not over heat surely coolant is
just water  the stat surely is not going
to fix its self  probably be opening temp
around 88 degrees c so half way on the
gauge would be no where that temp.

Would be pretty much halfway, bit harder to tell on the Mk1 because there is no numbers on the gauge but on pretty much all cars halfway on the temp gauge is 90 so its probably right.

Oh thats another thing, check your t-stat and your fan switch are the correct ratings

still the same question
did it over heat

going to put the kettle on
make a cuppa

no there is steam coming
out it must be boiling over
relief the stat has turned it
off

Well the good news is I found the issue and it's so simple, split hose running from the block to the thermo housing.
The coolant under heat would start to leak out and drip onto the exhaust manifold…..not much coolant at all but enough to cause lots of steam so it looked much worse than it actually was.

The bad news, the thermo housing is knackered too, sooooo fragile.

It looks like the part no longer exists from what I can tell (035919369), any ideas of an alternate solution?

At the moment I've ran a hose to bypass the housing and all is running ok but it must have been doing something so I would rather it be connected lol.

Does your look like this?

Kit if you don't have the thermostat already.

https://www.ebay.co.uk/itm/VW-GOLF-MK1-CABRIOLET-MK2-GTI-THERMOSTAT-COVER-KIT-C584/220983985218?epid=1043807109&hash=item3373ac0442:g:i2kAAMXQwKdRfjLq

Or the thermostat housing.
https://www.ebay.co.uk/itm/Mk1-2-golf-thermostat-housing/351995497089?hash=item51f4910a81:g:33oAAOSwuxFYuEjr

VW changed over to the plastic type for later cars I guess to save money, if yours is metal you cant buy new ones in this country only 2nd hand.

Thanks buddy, it's not the thermostat cover, that is all good. It's a sensor housing next to the block that's knackered, just corroded to dust on one edge so nothing for the hose to grip to.

Do you still have the original carb or has one fitted a Webber carb?

mark1gls said

Do you still have the original carb or has one fitted a Webber carb?

One has the original sir