Overheating

[johnnyroper]

I was lucky with mine the head was fine no replacement or skim required just new gaskets/bolts etc and all was good for the following 2.5 years and 30k of ownership.

[christiant]

Does anyone know the exact bit I need for the head bolts, as I want to be prepared when taking the cover off, thanks.

[johnnyroper]

Triple square/spline 12mm if memory serves correctly

[James Sharan TDI 4motion]

Hi guys.
My Sharan TDI 4motion is having overheating issues. I have read this thread in great detail and my symptoms are the same. Temperature went all the way up and told me to STOP in the dash. The expansion tank pressurising and bubbling sporadically like a volcano. The fans don't appear to cut in at all. The radiator seems to have a cool spot underneath the fan control switch as well. The blowers are cold all the time too.
So I started to investigate.
I removed the thermostat housing to check the condition. It seemed quite rusty and corroded so I swapped it out for the stat from my spares engine (which seemed to open a lot easier)
While the thermostat housing was removed, I checked the impeller on the water pump. I put the car in gear and rocked it back and forth whilst feeling the movement of the impeller. All seems fine with it. I was told the timing belt had been changed not long before I acquired the car.
I have been right through the pipework including. The T piece return to the expansion tank. All of that seems fine too.
The car has had the EGR cooler removed so the pipework for that has been bypassed correctly.
I've checked the secondary waterpump and im not sure whether it works. I've tried to probe the connections but I can't get the pump to work. (I tried the same with the pump off my spares car too with no joy as well)
I've checked the fans and the work on both speeds. I've also checked that the fan sensor operates the fans by using a blowtorch and that makes them work. They are both working ok.
After checking all these, I drove the car and it seemed to fixed. The temp gauge stayed happily around 90 degrees and I had hot air of the blowers. I was happy. I got home and checked the expansion tank and that was still bubbling violently so my happiness disappeared.
I drove it again about an hour later and my blowers were no longer hot but the temp gauge stayed around 90.
Since then, the temp gauge mainly stays at 90 but can go up to 105ish. Then go back to 90.
My question is do you guys think my head gasket is the cause of my remaining issues. I can't see any oil in the water or water in the oil. But ive heard that that does always happen on the PD engines.
Cheers for reading such a long post!

[johnnyroper]

Classic Pd head gasket symptoms you donââ,¬â,,¢t get oil in water or vice versa normally as itââ,¬â,,¢s combustion gasses passing from cylinder to cooling system.
A sniff test never normally shows anything up either as it needs to be under load to show any signs on these.

Head off job and you will see the black marking on gasket between cylinder and water jacket.

I was lucky it was obvious gasket failure and head was fine so no skim etc needed. Just hasket set,bolts,belt kit,fluids and filters etc.

[James Sharan TDI 4motion]

Bugger!
Thanks for you help though guys! 👍👍

[Chrispb]

Sounds like you have acquired someone else's  problem car.
Rusty coolant would indicate running with plain water which is not good.
Heavy pressurisation would indicate compression pressure being forced into the cooling system, almost certainly head gasket!! water pump if OK may have been changed when cam belt was done.
coolant needs to be contacting the thermo switch in the radiator for any chance of the fans working at the higher speed, while we're talking about fans does the fans run on slow speed when aircon is on? assuming your aircon does work.
Electric pump  should run all the time engine is running and carry on running for three minutes after switch off 115 AUY engine, it's common for the brushes to be worn out, there is a how to to repair these in the knowledge base.

[James Sharan TDI 4motion]

I've been running it on just water since I first encounter the overheating problem which was the MOT a month ago. I've only had it on the road since the 1st of august and only done about 70 miles in it.
It certainly does look like someone else's problem car. There are loads of things wrong with it. 😬😬
I was cheap and it came with a spares car though.
I think I'll try to do a sniff test and compression test on it to see what that shows but realistically I'll be doing the head gasket next weekend.

[johnnyroper]

The sniff and compression test will probably prove nothing in my opinion,like you say realistically will be having head off it.

[mickeywis]

Been too hot of late to work in the garage so will be taking the head off on Thursday for sure. Glad others have joined in on the conversation.

[mickeywis]

Hello All,
          I finally took the head off at the weekend. I was surprised that I can`t see any obvious signs of failure from the gasket. I have cleaned the head and given it as many straight edge checks as I can perform and can`t find any imperfections. I`ve put the head back on today with cambelt and will finish all other jobs at the weekend. I`m a little concerned about timing but everything went back as it should with with cam and crank clamped and marks on the belt. I`ve turned her over manually and all feels well.

Fingers crossed guys!!

Mickey

[johnnyroper]

Did you use the tools to lock cam and crank or just paint mark prior to removal? Also have you changed belt kit,water pump and thermostat while it is in bits?

[mickeywis]

Thanks Johnny,
            Used the proper clamping tools for cam and crank, I just marked the old belt to confirm settings. It made sense to change everything you mentioned whilst doing the job. So far, I`ve spent 7 hours of my time and Ã,£130 on parts.

Mickey

[johnnyroper]

It will be fine then if locked down with the tools,did you slacken off the 3 13mm cam sprocket to hub bolts when refitting the belt? If so try and get them back in same place or torsion angle will be off which can affect running/power.
I did a write up in red library about adjusting as mine needed tweaking post head/cam work to get it running ok.

Thatââ,¬â,,¢s a massive saving on what a garage would charge you,once back together should be all ok. If not done already check the restrictor in small bore return hose to expansion bottle is clear to help bleed air out. Run a 2mm drill bit down it.

[mickeywis]

Now going out to the garage and finishing the job off. Will be back later with my results!!

[mickeywis]

Well guys the job is complete, she is running again. I only did about a mile in her just to have a clear out of any shit. I`m still not 100% sure I`ve cured her yet, I`m no mechanic by trade I just have a bloody good tool kit, the internet and you guys!!. I`ll be in touch as she will be tested properly tomorrow. Thanks again for everyone`s input.

[johnnyroper]

Donââ,¬â,,¢t forget to check and top up the coolant a few times over next week or so as there will probably be air locks in system.

[mickeywis]

It`s only finally f###ing fixed!! To anyone else that reads this, don`t be in denial when it comes to a blown head gasket. The big positive with denial though, is that you change everything else before the head gasket so you end up with a bloody good car again!!

[johnnyroper]

Itââ,¬â,,¢s a very common Auy problem,glad itââ,¬â,,¢s all sorted now to just drive it without fear of overheating.

[christiant]

Did mine and drove about 500kms 300 miles in it, does the same as before. Gutted as did a lot of things to it, converted it to new style t-belt and blanked off egr, replaced the whole head etc... Drives sweet and then after long drive with lots of load it over pressurizes... I guess the block is cracked, as it does it in a very strange fashion unlike a gasket would and one of the pistons didn't rise as high as the other ones which indicates a bent rod and it being hydrolocked before... So i guess the only way to sort it is find another bottom end or engine, but I am not sure if i will continue with it....

[christiant]

Having more thoughts on this, so what it does is, after I shut it down after really long run in very hot weather, it spits coolant from aux heater area. It doesn't with engine running. When I look at the expansion tank, it sits at min mark then if I open it I hear a hiss and coolant goes straight over max. If open the coolant cap at cold I still hear a hiss. I did have a problem with my heater matrix inside cabin and fixed it only with rad weld. Could it be sucking air from there? The aux water pump is not working. Never looses coolant or over heats while driving even hard. Doesn't mix oil with coolant. I even touched the hoses after a long run and they seem not hard at all, the one coming out of thermostat is a bit harder, but nothing I would consider too much... Could the radiator be blocked?. I have a new thermostat, water pump, done the head and gasket. Right now just tried pumping the coolant system to 15psi and it holds the pressure for about 5 mins.... So that would rule out the cracked block...

[Chrispb]

So why did you not sort the run on pump.

[christiant]

So why did you not sort the run on pump.

No, I presumed it's not important... Could that be the reason? I will do asap and post results and I put a new expansion cap on, but haven't tested proper yet. Where I drive it is about 30c during the day. If that doesnt sort it I will put a new heather matrix on as mine was leaking and only fixed by rad weld I have some suspicion it could be sucking in air from there. A mystery... It runs a 100% right otherwise, had a long run on a mountain road and was pushing it hard to make sure didn't over heat. Also drove it at 80mph for a long time on 6th gear loads of boost, nothing unusual but then when I stopped and cut it off, did the same... Seems to pressurize only after a long hard run and after I cut it off... If I stop and leave it idling and I check the hoses, they don't seem hard at all...
So I will start with sorting the aux pump, as that's a cheap fix, if not I might replace the heather matrix, will check if all parts of the radiator do get equally hot which I haven't done yet. It doesnt seem to loose much coolant at all and doesnt use any oil. Sits at 90C all the time. Any other suggestions? Very, very strange...

[Chrispb]

The booster heater will not operate correctly without the pump working as the engine water pump is not sufficient to circulate coolant through the engine two heater matrix's  the booster heater and associated pipe work but more importantly the three minute run on after engine is switched off.

[johnnyroper]

The rad weld you put in could also be causing problems as it restricts/blocks cores inside rads and heater matrix.

If you do the matrix be prepared itââ,¬â,,¢s a big job on these,I did mine dash out,bulk head extension off and some well hidden bolts on bulkhead.

[brianh]

Also if your doing the matrix, be aware they are different between lefthand drive and righthand drive vehicles. I found this out by ending up with a lefthand one.

If you do replace the matrix its a good time to flush the system through and get rid of any remaining radweld (hosepipe in every opened end of pipe works well, just let it run till it runs clear). I wouldn't be surprised if thats whats stopped the run on pump working. If the matrix is leaking you will usually smell it if there is any antifreeze in the system, plus notice the screen misting up if your a/c isn't on or doesn't work.

[mickeywis]

The run on pump is a a job for a steady hand. But, for Ã,£3 for the parts to repair it, and some patience, worth doing for sure.

[christiant]

got the pump going, but definitely pressurizing,  I forgot to put the washers under the head bolts even though i was super careful with everything, so I guess It will come apart again. Very slight leak so I will attempt to just do new bolts and if it doesn't work, then will do a full head gasket again.

[johnnyroper]

That will cause it as bolts will be bottoming out and reaching full torque before head is clamped down fully.

If you do the head bolts one at a time make sure you go in sequence,change rocker and cam cap bolts again and also make sure itââ,¬â,,¢s cold and coolant cap is off so no pressure in system.

[christiant]

I spend so much time looking at other things, being too careful, measured everything and stuff, that it got so late when I dropped the new head on that it was pitch black dark and didnt see. I will do one at a time reverse sequence, hopefully the HG has no damage from combustion. It runs very well and only very slightly I feel it's pressurizing. It has a remap and the extra turbo pressure seems to be causing extra pressures in combustion chambers. Will do this ASAP and fingers crossed wont have to take it apart again... By the way the run on pump does matter in regards to air locks too. Definately when I replaced it, the system flowed a lot better.

[johnnyroper]

Yes without run on pump the engine pump struggled to circulate coolant through pipework to rear heater,also after switch off it helps reduce the risk of hotspots.

[mickeywis]

I took my old bus out for a good run today, it`s lovely with the head gasket done!! I couldn't use sixth gear before as she would heat up even with both fans bypassed and running permanently. After getting home I waited an hour then went back out and released the cap, NO PRESSURE RELEASED, happy days :-)  Time to start a new topic on clutch/gearbox.

[christiant]

Mine seems fixed with new 150 hp bolts again but with the washers this time+ flush deionized water new antifreeze and run on pump, thermostat and expansion cap. However when I flushed it this time my heather matrix started blowing steam due to flushing out all the rad weld I did flush it when I did the head but not fully, this time it seems I got it all out. So it's the front heater matrix left to do and it will be all good...

[brianh]

It isn't as bad a job as you'd expect, the worst bit i found was finding the second bolt for the dashboard (its hidden in the scuttle area behind the pollen filter casing, you can't see it directly but can feel it once you know where to look)

[Kristaps Baltais]

I have a question on AUY engine. I do not have had any overheating problems, and I tend to drive a lot of hills. My expansion tank has developed some oily, black residue on its walls over a year long period. I'm a bit confused, since PD engines do not usualy leak oil in coolant. Could it be leaky EGR cooler?

[Chrispb]

Maybe but more likely engine oil cooler also if you have auto transmission, transmission cooler.

[Kristaps Baltais]

Maybe but more likely engine oil cooler also if you have auto transmission, transmission cooler.

Then I will change both. I have manual, so no transmission cooler.

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[Django Williams]

Hiya.

My galaxy 2004 auy engine has been overheating recently. It was a 600 quid car. Cost me another 600 for mot. Not a mechanic or do I know anything about cars really.

I've ordered some stop leak online....I know I know but I don't have the money or knowledge of how to fix it properly and I'm just going to try and keep it running while I save up to get another galaxy/sharan/alahambra.

Does anyone know how to basically bridge it before it gets scrapped. Only need to keep it going for 4/5 months.

[Chrispb]

you could check out the water pumps (engine firstly then run on pump) as you may have a dodgy impeller other than that no you'd be wasting more money as you will have head gasket failure.

[Django Williams]

The water pump was changed about 2 years ago

[johnnyroper]

Was it the metal impeller type though? If it was plastic type then it could be loose on shaft.

When does it overheat? Usually these engines only overheat when under load like at speed,up hills or towing.

[Django Williams]

When going over 50/60 mph on a long journey. Hard acceleration. Expansion bottle fills up and shoots out as if it's being pumped out after filling up with steam It takes a while to do that though.

[Django Williams]

And I've not got a clue if it's metal or plastic

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[Django Williams]

you could check out the water pumps (engine firstly then run on pump) as you may have a dodgy impeller other than that no you'd be wasting more money as you will have head gasket failure.

Im 99% certain the head gasket has blown. But I'm just looking to keep it running. Not prepared to put more money into it as there is simply too much to do

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[johnnyroper]

I donââ,¬â,,¢t think thereââ,¬â,,¢s a lot you can do to limp it along until you change it,rad weld type stuff wonââ,¬â,,¢t work. Only thing I can think is removing thermostat might reduce the overheating.

[Django Williams]

I donââ,¬â,,¢t think thereââ,¬â,,¢s a lot you can do to limp it along until you change it,rad weld type stuff wonââ,¬â,,¢t work. Only thing I can think is removing thermostat might reduce the overheating.

Or maybe just leave the expansion cap off and keep topping it up. It's the build up of pressure that causes the biggest problem. I originally thought it was just an air lock. Heaters were working yesterday at the front. Put more coolant in it and put the cap on. Woke up this morning and no coolant hardly. I've not noticed any loss of power or rough idle. I just know I'm going to get rid asap when I have the money lol

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[brianh]

Or maybe just leave the expansion cap off and keep topping it up. It's the build up of pressure that causes the biggest problem. I originally thought it was just an air lock. Heaters were working yesterday at the front. Put more coolant in it and put the cap on. Woke up this morning and no coolant hardly. I've not noticed any loss of power or rough idle. I just know I'm going to get rid asap when I have the money lol

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Might be worth checking the radiator is actually getting warm - a blocked rad could account for you having problems at that sort of speed (flushing out with hose may improve it if so). If you don't have an actual leak the stop leak type products will only make the problem worse (blowing coolant out of the expansion cap isn't a leak, its the result of either combustion pressure leaking into the coolant, or poor coolant circulation causing the high pressure to be generated).

[Django Williams]

Might be worth checking the radiator is actually getting warm - a blocked rad could account for you having problems at that sort of speed (flushing out with hose may improve it if so). If you don't have an actual leak the stop leak type products will only make the problem worse (blowing coolant out of the expansion cap isn't a leak, its the result of either combustion pressure leaking into the coolant, or poor coolant circulation causing the high pressure to be generated).

So it could still be an air lock? Or blockage. I've done the conventional head gasket tests. Looked for mayo in oil cap. Looked for oil or small little bubbles when you first start it up. Got on all 4s and sniffed my exhaust when it's been running and got the missus to tell me if I get the white smoke and none of them seem to be evident. When I squeezed the radiator hose I could hear the gurgling sound and topped it up. Left the cap off and ran it with heaters on max....yesterday Got warm. Now it's only slightly warmer than cold. Also I only noticed it at the weekend on a 100 mile run when about 30 minutes in. The temperature gauge was beeping and flashing. Then I pulled over. Saw my coolant was literally filling the entire resovior tank. Opened it up and the stuff went everywhere.

Struggled to start but soon kicked in after a second or 2 and it done the rest of the trip with temp gauge fluctuating between 90 and 120 degrees....more so uphill or going over 50/60 And the gauge would go up quite quick.

I had just topped the coolant up and never bled it because I honestly didn't know I had to or how to. I thought it was like if you have to top the oil up lol #imadumbasswithcars.

But it drives ok. Starts Ok. No rough idle. Apart from temperature gauge going up and heater being only slightly warmer than the reception Gary glitter would get if he walked into a school.

Obviously I suspect the head gasket (if it is how long would it last with nursing it) but kind of hoping it's down to me not bleeding it of air properly and causing and airlock lol

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[johnnyroper]

I would put money on head gasket with those symptoms,on the diesels unless you are on a decent run the thermostat will not be opening especially now weather is getting colder.
The overheating will be down to combustion gasses in cooling system causing excessive pressure so coolant is not circulating correctly,it is instead pushing it up and out of the expansion cap pressure release.

Taking stat out and allowing a bigger cooling circuit all the time might help by making it go longer before boiling up,but apart from doing the head there is no other way of resolving it.
I have been there with the PD lump in my old gal.