my 98.5 A4 1.8t is overheating. the car has 118,000 miles. the engine was rebuilt at 95,000 miles due to the previous owner being such a idiot he let the timing belt break, so im having a hard time beliveing its the head gasket, but ya never know.
this is what ive replaced so far:
1. I replaced my radiator, seconday radiator fan (cause it wasn't turning on, but a tech told me it was due to a fan switch sensor?), and my oil cooler about 5000 miles ago due to a heating problem and it went away was fine until about 4 months later when i was driving on the freeway it started to get really hot and thats weird cause i was highway driving?
so after the second heating probley I've replace: thermostat, coolant temp sensor, fan switch sensor( and i got the lower temp fan switch) for the secondary fan to turn on but that still dosnt turn on? and thats all ive replaced.
i was just looking if anyone had similar problems and could help me out? this is my only car and i need it fixed fast. im good with cars so ill probley be fixing it myself just dont know what to fix. i think the next thing to get would be a water pump? any thing else i should replace that im forgeting? or anything that has to do with cooling? all help is really appriciated and thanks for all the help.

audianthony

 

When your car is overheating, have you noticed what your water level is in the coolant resevoir? You may have a slow leak somewhere and eventually it starts to overheat. It may be leaking from a hose or the water pump. Does it overheat consistently?

 

those water pumps were notorious for the plastic impeller coming apart, especially in the 1.8ts.... id remove the thermostat housing and you can see the water pump impeller from there.. see if it spins freely.. if so then its dislodged and so yeah.. you need a new water pump...

 

Are you loosing coolant? You know, do you constantly have to add coolant for it to runfor a short distant? If so you need to fix the leak. My 00 A4 1.8t had a overheating problem previously it turned out to have a crack on a plastic coolant elbow piece kinda looks like a thermostat housing on the back of the block( longitudinally mounted 1.8T).

If the overheating problem happens at slow speeds or at idle and then cools down once driven its the water pump.

Check the fans if they turn on.

My audi had a mechanically belt driven fan and a electric fan for the AC. I recently replaced both and went to electrical. ( Now AC blows colds all day and oil temps stay down plus increased fuel mileage)

 

Prizmatik: Yes it over heats consistently and ive noticed i was loosing a little coolant but i thought that was due to it getting so hot it boiled out of the overflow resivor, but i could have a leak? ill check my water pump and hoses. the coolant that leak is right under the coolant resivor cause it gets coolant on my oil filter and tranny hoses and stuff. alomost looks as if it sprays coolant on my oil filter enige down there?

Bigern45: i dont have the 1.8ts i dont think? but ill check the water pump impeller out. darn i just replaced my thermostat the other day didnt even think about looking at the impeller. So if the impeller spins freely its broken?

Splbasshead: im loosing alittle coolant but like i said eairlier i thought that was cause it was boiling out of my coolant resivor overflow cause the coolant was sprayed under the coolant resivor all over my oil filter and stuff. but i haven driven it much just to my house when i noticed it got hot then i replaced, Tstat, coolant temp sensor, and fan switch sensor (got the lower temp fan switch). and drove and it overheated like before. was your leaking from the piece the coolant temp sensor goes in? and it overheats at idle or driving and dosnt cool down even on the freeway. i replaced my secondary fan, thats the one on the turbo side and the fan switch sensor( the one that goes into the radiator to tell the fan when to switch on and it still dosnt turn on? what could that be?

well all the help is appriciated and thanks. im gonna check all these things and feel free to write me back cause i need to fix this asap. also will a cel scanner tell me the problems?

 

You may have a leak in the area you specified. There is a rubber coolant hose in the oil filter area, it is hard to see unless you remove the coolant resevoir and rubber hose that connects to the throttle body. I recently replaced this hose on my 1997 a4 1.8T due to a small leak it had. Its time to find where that leak is coming from. Good Luck!

 

you say in your signature and such that you do have a 1.8t.. and yes.. any type of play with the impeller is bad news..

 

Yes I do have a 1.8t but i miss understood you. i thought you meant the 1.8ts( the sport one) but you meant 1.8t's in general. Today i drained my coolant and took out my thermostat to look at the impeller and i could spin it, it was kinda hard to spin but it did so im just gonna get a new water pump. hopefully that fixes the problem well thanks and ill post the end result.

 

yeah the water pump is belt driven, so if you could spin it by hand then it has broken somehow off the shaft.. man.. i was working on a 97 1.8t and it took me forever to diag this problem.. the only thing that got me on to it was the fact that the car would fire up and run and start to over heat, and the coolant in the radiator was like ice cold.. so there was no circulation.. and it was due to a water pump impeller completely falling apart.. hope its your problem and you get it resolved brother...

 

Yeah it took me a few days to figure this one out. But I'm pritty sure it's the water pump. Yeah and like you said my car fires up and drives fine it just gets hot. So I'm gonna be replacing water pump in a few days.