Help, Overheating.

Volkswagen CL Umwelt TD Estate. 1.9 AAZ engine 1998 S reg.

Emptied cooling system yesterday. Refilled using the recommended antifreeze. Today after driving around 15 miles the car overheated, smoke from bonnet, kind of burning smell. Shut off straight away and called the RAC, they arrived after about 45 minutes by which time things had cooled down. He said he wasn't sure but thinks it may be the water pump. He told us to drive home (about half a mile) slowly and switch off at traffic lights etc. he followed us, just as we got home the temp guage shot to 90 (no smoke this time but faint smell)

The main thing I was wondering was could it be an air lock instead of the water pump, top and bottom hoses seem at the correct temp (bottom one cooler than top, but still pretty warm) the fans did kick in and off again after we refilled at the coolent change, but I don't think it took in as much water as it should. This being the first Volkswagen I have owned, previous cars having had bleeders.

Any advice would be greatly appreciated, thanks, Mandie.

Reply to
shpams
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Was the coolant tank full after all this, or had the level dropped? Usually, if there's a bubble in the system, it'll work itself out and the coolant in the tank will suddenly suck down into the system when the thermostat opens, at the latest. If the coolant level stayed the same, then the pump is as good a suspect as any. It would be quite a coincidence, but VW water pumps do have a history of frequent failure.

Reply to
Brian Running

Thanks for your reply, The tank stayed pretty much the same, Guess the gunk of the old coolent mix was holding it together :-) Any tips on putting a new pump in?

Reply to
shpams

Did you refill with the recommended quantity? If the book shows a capacity of 5 liters and you only installed 3 liters then you could of had a heck of a big bubble of air. I try to measure waht I put in so I can guess f I have abig bubble that needs to be bled somehow. The old Rabbits/Golfs required a variety of tricks to get the air out of the system. Basically I recall it as the removal of a hose to dump antifreeze in. My 2003 tdi did not seem to require any burping but maybe I forgot a burping after I replaced the water pump. I do keep the cap off the resevoir to watch how the water is flowing. On a vehicle that has a cap on the top of the radiator I watch for burps and siginificant drops in antifreeze level before I drive it anywhere. Once again measuring things as I go if i have drained the block and replaced the water pump.

Another th>Volkswagen CL Umwelt TD Estate. 1.9 AAZ engine 1998 S reg.

Reply to
Jim Behning

Well, just because the coolant level didn't suck down, it's not conclusive that you need a new pump, it's just a statistical likelihood. It could still be a big airlock, but I haven't had a problem with that in my newer VWs, they've been good for me about taking coolant. On my old one, I used to take the upper hose off the radiator and pour coolant into it, to get the block filled. It would not take coolant through the overflow tank very well at all. While it's true that VW water pumps are unreliable, I'd also hate to see you jump to the wrong conclusion based on that fact alone. Can you tell if there's coolant in the top hose? Maybe pull it to verify, and pour coolant directly into the hose.

I'm not familiar with the 1.9 AAZ engine, but if it's a design that drives the water pump from the timing belt, then go ahead and replace the timing belt and tensioner at the same time.

Reply to
Brian Running

Thanks for your reply, Stupidly we never filled from a measured water can, we just topped up until it would take no more. I got a water pump and timing belt today and we will fit them tommorrow, Definatly using a container that will let us know how much goes in.

Reply to
shpams

I got a pump and timing belt earlier, (amazed at how fragile the pump looks compared to my partners Cavalier. We can not get time to work on the car today, but will get it done tommorrow. I will check the top hose before starting any work on it. The timing belt and tensioner was changed less than1000 miles ago which was in December, the car is mainly used for local driving for my disabled Mum (her scooter fits in the back) would the tensioner need to be changed again? The car has 184000 on the clock and I have no idea when the pump was fitted, if it is the pump that's taught me a lesson, should have done it along with the timing belt and tensioner :-)

Reply to
shpams

Scanning the parts catalogs quickly, it looks to me that the AAZ engine does not drive the water pump off the timing belt, the pump is nothing like the ones on the engines that run off the timing belt. So your recent work probably has no bearing on your current problem. That's the good news, I guess.

Reply to
Brian Running

I was relieved to find that today. I put a new water pump in, have to say the old one didn't seem too bad, just a little bit stiffer to turn with a very gentle touch, about the same with normal. The impellers were whole. Put a new timing belt on seeing as I had to remove the other one to get to the water pump. Put it all back together and started filling the cooling system, this time I removed the top hose and filled through there as well, it took a bit more water and coolant this time round. The heater blew hot and the fans kicked in and back off (they did this last time as well though) I ran out of time to put the belly pan on and I haven't taken it for a run yet, I will do this tommorrow. The temperature goes to 90 and stays there, it done that last time and gave no indication gauge wize and gave no warning lights to let us know it was going to overheat, the smoke and burning smell was what gave it away :-( On a rough guess I would say the job should have taked around 2 hours, it only took me 7.5 hours.

Reply to
shpams

Doh... forgot to mention I had a flat bettery in the week, and today after running the car for quite a while I went to turn the ignition and flat again. Seeing as it's the fan belt that drives the water pump thought it would be of some significance, the belt did not seem slack.

Reply to
shpams

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