Little help needed troubleshooting overheating

SouperComputer

Im 85% sure the head gasket has gone, but I thought Id get other's opinions.

Its a 1997 B5 1.6L Petrol Passat

Basically driving on the motorway, water temp warning came on. Put heating on full, slowed down and the temp dropped a little after a LONG time.

Pulled off the road at the next exit, was hoping I had blocked the radiator with a bag or somthing, no joy. Water level had dropped just below the min mark, oil was half way up the dipstick. No sign of a water leak, however some oil was seeping from the top cover onto the exhaust. Topped up the water. Also noticed while the engine was running, a lot of steam coming from the oil cap when removed, although it was very sunny and I hadnt looked as closely before, so I could have been over-analysing.

Let the engine cool down and drove on. Temp shot up, basically had to drive at 35Mph to keep the temp within range. Stopped after a while, water level again just below min. Topped up again.

Any thoughts on another cause for this?

BrianD3

Flow of coolant around the system could be an issue. This could be due to a thermostat not opening properly or an internal blockage in the rad. Also coud be a water pump problem (does the 1.6 Passat have one of those infamous VW water pumps with the plastic impellers which shear off)

I would say it's more likely to be one of the above than a blown head gasket actually.

Also your temp gauge/light could be faulty I know of a few cases where this was the cause of "overheating"

Is the car actually using coolant? You cannot really tell if the coolant is down slightly by checking the level in a hot engine as the level will vary anyway. Check the coolant when cold, drive the car and get it good and hot, let it cool down again and then recheck the level

Kersh

Very interesting for this subject to come up. In the past 2 days I have seen 2 cars suddenly bellow out tons of oil smoke/steam as they travelled along. Both pulled over, and both were german, a passat, and an Octavia.... whats going on...

cantdecide

i had smoke bellowing from the back of my last tdi A4 recently and it turned out to a cracked pipe near the turbo. i've never heard of a passat needing a head gasket (but no doubt someone has)

junkyard

As BrianD3 said its more than likely one of VWs famous waterpumps, they really are rubbish cars in the last few years.

11811

Same thing happened my 1.6 golf.Its the water pump,got mine fixed under warranty but i was told its not a huge job.

SouperComputer

Thanks for the replies folks. Im going to take it for a spin today to confirm if it is eating water.

IIRC it was the 1.8's had the infamous plastic impeller water pump.

Judging by the plugs, its definately getting warm in there, even if the temp guage\sensor is out. Im also pretty sure I heard some bubbling noises from the cooling system when I stopped the car. But then again, I have never listened so closely to it so its hard to say.


Someone on passatworld mentioned a possible oil cooler issue, but I think that only apples to 1.8 Turbo's.

Ive never heard of a head gasket go on an 8V passat either

BrianD3

When you drive it check that the hoses and the radiator get hot. If parts of the rad or hoses are colder than other parts then you coudl have a blockage When checking the rad, be v. careful with the fan!

Also if your engine is overheating but the radiator top hose is cool or lukewarm then the themostat may be sluggish to open or not opening fully.

It could also be that in a 1997 car the cooling system just isn't working as efficently as it should be due to old coolant and build up of scale in the radiator. It could have been like that for ages but it only became critical in the recent hot weather. A coolant flush might improve things but the car may still run a bit hotter than it did when new.

My money's still on the water pump though. A quick google seems to suggest that the 1.6 VWs do have plastic water pump impellers and failures are common. When was the pump last changed (if ever)

SouperComputer

When you drive it check that the hoses and the radiator get hot. If parts of the rad or hoses are colder than other parts then you coudl have a blockage When checking the rad, be v. careful with the fan!

Yea, ill doin some troubleshooting today . Fan is on a viscous, so at least I dont have to worry about it coming on suddenly.

It could also be that in a 1997 car the cooling system just isn't working as efficently as it should be due to old coolant and build up of scale in the radiator. It could have been like that for ages but it only became critical in the recent hot weather. A coolant flush might improve things but the car may still run a bit hotter than it did when new.

Im hoping this is the case. The temp really shoots up though, if the engine is idling its okay, but if I drive it and use anymore than 1\8th throttle, the temp goes up very quick.

My money's still on the water pump though. A quick google seems to suggest that the 1.6 VWs do have plastic water pump impellers and failures are common. When was the pump last changed (if ever)

Thanks for the info re the pump. Tbelt was done @ 56k, im at 98K now and im going to sell the car soon so ill do the whole lot if needed.

SouperComputer

No prizes for getting this one! Did the Tbelt and Aux belt too, if nothing else it will give peace of mind to the next owner.

Thanks to those who helped