coolant change.....2litre 16v

[dubweiser 0]

I am about to change my coolant and i have bought my g12 and i was looking on the forum and found a post on how to do it but i think it was for a vr6.I dont know if this is the same for my car but if it is then i guess i just didnt understand what was being said(plastic transfer tubes n stuff with drain plugs in them??????????).Does anyone know or have a step by step guide for eejits on how to change the coolant on this model please.Cheers

[Guest]

i heard you should use g12 plus...its better they say....i had mne done, there is a thermo plug at the bottom of the radiator (RHS)....u need to take it out and it should drain out..............

[davidwort 0]

I am about to change my coolant and i have bought my g12 and i was looking on the forum and found a post on how to do it but i think it was for a vr6.I dont know if this is the same for my car but if it is then i guess i just didnt understand what was being said(plastic transfer tubes n stuff with drain plugs in them??????????).Does anyone know or have a step by step guide for eejits on how to change the coolant on this model please.Cheers

 

I've always undone my rad bottom hose and left it to drain out (shouldn't let it go down a rain drain though) then fill it with tap water alone (at least until water is in the rad top hose) and run the engine for a while to flush the system round, then drain that off and re-fill with distilled water (5L bottle from Halfords) plus your required percentage of anti-freeze. Whole system is over 6 litres I think.

Don't forget to put your heater on full or water and coolant will be trapped in the heater matrix. It also helps to release the top hose a bit to let the water fill the system, 16v's tend to trap air pockets and an over-heated head is not good news - keep track of how much you've put in, 5L or more would be good before starting the car.

Check regularly after the first few trips and top up header tank as required.

 

David.

[Henny 0]

Don't forget to put your heater on full or water and coolant will be trapped in the heater matrix

Not on a Corrado it won't... this is a common myth, it won't make a blind bit of difference as the Corrado heater valving controls the air flow NOT the coolant flow... The Matrix on a Corrado is always filled with the same temp coolant as the engine bay's pipes... 8)

[davidwort 0]

Don't forget to put your heater on full or water and coolant will be trapped in the heater matrix

Not on a Corrado it won't... this is a common myth, it won't make a blind bit of difference as the Corrado heater valving controls the air flow NOT the coolant flow... The Matrix on a Corrado is always filled with the same temp coolant as the engine bay's pipes... 8)

 

D'oh! .. now you come to mention it quite a few things have changed on VW's since my Polo Coupe, which reminds me, anyone know the part number for a set of new points for my C, they must be knackered by now 135,000 miles without changing :wink:

 

David.

[Kevin Bacon 5]

The MK1 Golf needed to have the heater on full :wink: But as Henny said, the MK2/3 and Corrado have the heater in circuit permanently - but having the temp dial on full hot helps disperse engine heat though.....but doing that fries the Head Unit though :?

[dubweiser 0]

so i just have to undo my top and bottom radiator hoses then?is that it.Is there no drain plugs in the block or anything like that.Sounds a bit too easy to me.Am i missing something i dont want to balls it up when i do it??????????

[CazzaVR 0]

It really is that easy mate :) . A word of advice- don't be too heavy handed taking the top rad hose off- ease it off as gently as you can. I was a touch over zealous with mine and cracked the plastic connector bit (between rad and hose) around one of the bolts- couldn't be fixed and guess what? VW don't supply it seperately :mad: Didn't have time to search the local breakers, so had to buy a whole new rad :(

 

Also, when you think you've added enough water/coolant, give the larger hoses a good massage (oo-er!) to get rid of any air pockets.

[Henny 0]

VW don't supply it seperately

 

GSF and Euro do though... ;) (yup, did the same myself! :oops: :lol: )

[dubweiser 0]

cheers andy.I was just a bit confused as the "how to" i read on here mentioned drain plugs and plastic transfer tubes and what not.Guess it must be for a vr6.Didnt realise it was just as simple as taking the hoses off then re filling it(via the header tank i assume?).PS ive never seen a storm trooper do that before..What would lord vader say

[Henny 0]

you need to refill it via the top hose (disconnect from the rad and pour into the engine through the rubber pipe) to avoid airlocks... When the coolant is at the top of the top hose, connect it back onto the radiator, and then top up through the expansion tank... 8) (same method should be used on all VW engines.... 8) )

[dubweiser 0]

so theres no drain plugs in the block or anywhere else that i should know about?

Cheers guys and a merry xmas to all u crazy kids out there :lol:

[deag 0]

Hi,

Did pretty much this exact process on my 16V a while back, coolant levels all seem fine (just topped it up recently).

But ever since the change, the water temp is reading around 70 (ie- it barely moves off bottom).

It used to sit at about 90, as you would expect, but since my coolant renewal, something's wrong.

Having read a few posts/threads on the topic of temp gauges, it seems this may not be uncommon.

Can anyone enlighten me?

 

Thanks,

 

Deag.

[CazzaVR 0]

GSF and Euro do though... (yup, did the same myself!

 

Henny, you've got to be kidding me! :mad: That cost me loads, and was the straw that broke the camel's back with my blackberry VR... :mad: :mad: :mad:

 

Nevermind, you live and learn :roll:

 

Yeh, don't think Lord Vader would aprove- but what he doesn't know can't hurt him :wink: :lol:

[Henny 0]

Sorry, AndyVR6, I'm not kidding... :| AFAIK, it's the same part on all Corrados and I think it's also used on Passats and possibly MKIII golfs too... :| I've had 2 of 'em now, one when I broke the original one getting the top hose off, and one when I changed the radiator as I decided it'd be a good idea to swap every part of the coolant system at the same time to prevent any leaks... 8)

[saysomestuff 0]

I've just replaced the heater matrix and my '92 16v is still overheating! Its losing loads of water but i can't see a leak at all, apart from a tiny air leak in the gasket that connects the matrix pipes to the engine - there is no way this is enough to empty the header tank in 15 miles!

 

extra info - When the matrix went last week, the AA man bypassed it and said the system was building up excessive pressure and overheating. Head gasket is fine as there are no combustion gases in the coolant system and vice versa.

 

This is driving me mad :mad: - Any suggestions?

[2cc 0]

IMO the AA man is talking round things. But that said, if you are loing a header tank full in 15 mls I would expect you would be able to detect steam venting (from wherever the leak is) when she's up to temp. It'll come out as steam cos, as the AA man rightly said the coolant will be at pressure and will boil off when escaping to the outside world. Favourites are: hoses, the two plasticky things that join the pipework to the block, the header tank cracked, or the cap itself (I believe it has a pressure relief valve in built but may be wrong on this one). Oh, I'd reconnect the matrix by the way.

HTH

[saysomestuff 0]

thanks 2CC - I'll get it up to temp and see if i can spot any steam. Lol just realised you're from Trowbridge, i'm from Westbury! (living in Cardiff at the mo) Any good 'rado mechanics round that way?

 

BTW if i wasnt clear,the AA just bypassed the matrix to get me home last week, I replaced the matrix with a new one on the weekend (nice job :) )

[davidwort 0]

I've just replaced the heater matrix and my '92 16v is still overheating! Its losing loads of water but i can't see a leak at all, apart from a tiny air leak in the gasket that connects the matrix pipes to the engine - there is no way this is enough to empty the header tank in 15 miles!

 

extra info - When the matrix went last week, the AA man bypassed it and said the system was building up excessive pressure and overheating. Head gasket is fine as there are no combustion gases in the coolant system and vice versa.

 

This is driving me mad :mad: - Any suggestions?

 

I know it sounds silly, but have you checked the expansion tank cap has a seal on it?

They can come off when you unscrew the cap and it can give symptoms like a head gasket failure.

 

David.

[saysomestuff 0]

This has actually got me thinking - it overheated after the AA man patched it which i attributed to the fact that the system had no heat exchanger so was smaller/under more pressure etc.

 

When i pulled over steam was coming out of the expansion cap. i thought it was like a failsafe to save the gaskets but is this not the case? Should steam categorically NEVER escape fromthe expansion cap?

[Henny 0]

there's a pressure release valve in the cap... odds are that if it's overheated and steamed, you'll need a new cap+seal... 8)

 

Good news is that they're cheap, available from GSF, Euro, Halfords, and VAG... 8)

[saysomestuff 0]

ah so thats a "no steam should never escape from the cap" :oops: - nice one i will nip into GSF on the way home

[Henny 0]

it's supposed to be a sealed system (the pressure helps make the boiling temp of the coolant higher) so any leaks will result in lowering the system's efficiency and lead to eventual overheating...

 

Steam's never a good sign... :|

[2cc 0]

Aha, looks like the caps your culprit then. And I used to think the AA were pretty good but this should have been simple stuff for him as its leaking as bad as you say! Still, we all have off days...

[saysomestuff 0]

hmm, i nicked an o ring from maintenance and the car made it home last night - when i stopped it was at 120c, i had a look under the bonnet to see where the leak was and there was steam coming out of the expansion tank at the bottom. and the goddamn fan wasn't spinning - the mystery unfolds.....

 

I guess the fan switch or thermostat has packed in, causing the system to get too hot, blow the heater matrix and several other bits and bobs. I'm going to bridge the connection so the fans on constantly and see what effect that has. There's no point replacing things if they'll just blow again!

 

Then it looks like a new thermo and re flush the system on the weekend :roll:

Such is life :?