Hi all,

Over the past 6 months or so I've come across a few issues regarding my automatic S40, and have been dealing with them with some advice from a mechanic friend of mine.

The car is a 1999 S40 with 153,000 km, I bought it 4 years ago when it was sitting at about 100,000 km.

This summer I completed four long drives along the Australian east coast going between Melbourne and Newcastle (four 850 km trips, all completed in one day) with no real issues apart from my old radiator cracking after the first trip up to Newcastle.

I had no other issues until I returned back to Melbourne in late February. The first issue I came across was that on cold starts, the engine would seem to start only on 3 cylinders. If I was quick enough, I could rev the engine while parked to clear this and it would then start to run on 4 cylinders. Only twice have I missed this opportunity to clear it and the car has conked out completely. Both times I was able to run the ignition while pushing the accelerator pedal to get it to start again.

An independent mechanic believed that this issue could be the sign of a head gasket blowing, and that the car wouldn't last too much longer. My mechanic friend wasn't as sure of this, but suggested we first replace the spark plugs (didn't make a difference) and when it came to a point where I could no longer clear the issue, we could try running Chemiweld through the car to see if this could act as a cheap fix for any potential broken head gasket issue.

In the past month or so, I've still been able to clear the cylinder issue just fine, but have begun to notice something else that I haven't seen before, even during a cold winter in Australia. The temperature gauge after a cold start sits at its lowest, and then increases to about halfway where the car then runs fine. However when it does start cold, on flat the engine doesn't respond to me pushing down the accelerator pedal very well unless I floor it - sometimes it seems like the engine's about to conk out as nothing at all is happening, but then at the last moment the connection seems to be made and the car finally accelerates. This issue disappears when the engine is warmer/the temperature gauge is reading a warmer engine (about halfway on the gauge).

Finally, another thing that's been happening in tandem with the acceleration issue is that the left radiator fan will stay on and be very loud for 1-1.5 minutes after cutting the engine.

My gut tells me these issues are related, and that there could be something wrong with the temp gauge/ETC that is making the radiator stay on, making the engine cool quicker, and thus not helping the acceleration issue on a cold start.

During regular driving (any time excluding ignition on/off) the car runs fine.

Please let me know if you guys have any advice for me!

Thanks a lot,
Angus.

 

yes a wonky ECT will affect the temp gauge and can cause the cooling fan to run on after shut down for a few minutes. Probably a good idea to replace as well as the thermostat. As to the head gasket question, there are a few tests like measuring the cooling system pressure (or feeling if the hoses get really hard), test for HCs in the coolant, check for foamy oil, do a compression test (dry/wet) etc. ECTs are fairly cheap under $50 and can be removed without draining the cooling system (you will lose about a half pint or less if you have the nose of the car higher than the tail)