98 VW Polo cuts out

daywalker

Hi,

I have a 98 Polo 1.0ltr, that has developed a severe problem in the last couple of days, it will not run once the engine warms up, it will start when cold but once the engine has gone past 70c on the gauge it will cut out and refuse to start, also when trying to restart it will turn over for 5-10 secs then you hear a clunk and then it will turn over for 5-10 secs again before getting the sound again, but if engine cold you don't hear this. On a side note when I removed the oil filler cap there was this yellowish gunk on it.

Any help appreciated? Or would I be better off availing of the scrappage offers and get a nearly new motor.

Regards,
daywalker

Technoprisoner

try a coolant temp sensor in her....sometimes when faulty they send a wrong siginal to the ecu telling it that the car is still cold so the ecu is trying to heat the car up like and automatic choke

andyseadog

we wont have this arguement again so soon

Technoprisoner

andyseadog wrote: »

we wont have this arguement again so soon

lol opinions are good ....the reason i think its this is because the car is ok when cold but when its up to temp it causes trouble...tehn again the lambda probe doesnt work untill the car is up to temp either...but for the sake of €20 id through a temp sensor in her

andyseadog

thing to do would be to start the car and unplug both sensors in turn and see if theres a difference in how it runs. this will give you a good indication as to how they are performing

Technoprisoner

you could try reading the voltage from the lambda probe with a multimeter to rule that out. You are looking to see the voltage regulating itself between .1 and .9v. if the voltage just stays the same you have a faulty lambda probe.. also make sure the car is up to operating temputure before testing as you need the car to be running in closed loop.

daywalker

Since my last post, I have managed to get the car started, but when it warms up it will conk out, I then removed the cap on the pressure vessel for the coolant, started the car it will run, though it tends to chug when warm, but if you screw on the cap, after 30 secs, presumably the time it takes to pressurize the cooling system, the car cuts out, a friend suggested head gasket failure, could he be right?

P.S. also both the oil and coolant levels had dropped below the minimum and I refilled them.

Muckie

I'd also take off the air breather and check if the "fatty gunk"

has clogged in here. Its a common problem on VW's.

Check on the left handside as your looking into the engine

and theres a half inch pipe that runs from the bottom of the

engine that coonects into the bottom of the air breather, this often gets

clogged. I've cleaned theses out using WD40, coat hanger and rags.

messy but does the job. Good luck.

daywalker

Since my last post i managed to get the car to a garage, where i have had new head gasket fitted( the old one was damaged according to mechanic), water pump, timing belt and the oil and coolant were replaced. I got the car home from the garage ok, but i've noticed that when starting from cold the car has a tendency to hunt once temp reaches above 50c and if the car is running idle it has cut out on me, but once the car is up to full operating temp it works fine.

Does the new head gasket need a time to bed in, so to speak, or should i bring it straight back to the garage to be checked further?

Lurching

Bring it straight back. It doesnt take time to bed in!

mondeo

You probably spent a fortune getting that head gasket done and now your pretty much back to square one. I was always under the impression that engine cutting out and not starting when hot was a crank position sensor. This happened on my Alfas ALL THE TIME!