1998 1.8 S40 overheating and interior heater problem

[Dave500]

Hi all. A newbie here. I just picked up a 1998 1.8 S40 as a runaround but it has a couple of problems I am hoping someone can give me some advice on. Apologies if these have been dealt with elsewhere. I did do a forum search but didn't manage to find the exact problems.

Okay problem one:

I bought the car about 65 miles from my home and noticed I wasn't getting any warmer. The interior blower is working fine on all speed settings but I wasn't getting any heat. I pulled over for petrol and when I set off again I noticed some odd gurgling noises from behind the dash and then the heater started working okay. However, it now appears to just work whenever it feels like it. Would appreciate any ideas.

Problem two:

After driving the car the 65 miles from where I bought it, a cloud of steam poured from under the bonnet and the temperature warning came on, telling me to stop. The engine temp was reading 130 degrees (I have no idea what a normal reading is). After the engine cooled a little, I added some water and coolant (it was a little low but nothing major) and went for a low speed drive. The temperature didn't get above 100 but then I didn't get above 30MPH. However, when I stopped the car, one of the radiator fans remained on for some time. If it wasn't for the cloud of steam earlier I might have assumed it was a faulty sensor or something but I guess there is a genuine cooling issue.

Again any ideas would be greatly appreciated.

Thanks in advance!

[Dave500]

Okay some Googling leads me to believe that the two problems are actually one problem. A failed matrix wouldn't lead to the engine overheating I wouldn't think. Does a blockage or leak sound likely to anyone?

[Ragamuffin]

I would be looking at an air lock, or more likely a faulty thermostat.

[Dave500]

Originally Posted by Ragamuffin

I would be looking at an air lock, or more likely a faulty thermostat.

Thanks!

Air lock sounds promising. Do you happen to know if the S40 has a burp valve anywhere?

[Dave500]

Can anyone point me in the right direction of the bleeder valve please? Many thanks!

[stevo48]

Sounds to me like your thermostat needs replacing, then fill to the required level with the correct mix of coolant and anti freeze 50/50 mix, the engine coolant should then pressurize normally and clear any airlocks with normal running. Keep an eye on the coolant level for a week or so to make sure your levels stay normal.
It might be worth checking under the oil filler cap for signs of emulsification (oil and water mix) and also look for traces of oil in the coolant header tank as if that is present it could indicate possible head gasket failure which could cause over heating.
Edit; as far as I am aware there is no bleed valve, but I stand to be corrected if I am wrong.

[Dave500]

Originally Posted by stevo48

Sounds to me like your thermostat needs replacing, then fill to the required level with the correct mix of coolant and anti freeze 50/50 mix, the engine coolant should then pressurize normally and clear any airlocks with normal running. Keep an eye on the coolant level for a week or so to make sure your levels stay normal.
It might be worth checking under the oil filler cap for signs of emulsification (oil and water mix) and also look for traces of oil in the coolant header tank as if that is present it could indicate possible head gasket failure which could cause over heating.
Edit; as far as I am aware there is no bleed valve, but I stand to be corrected if I am wrong.

Thanks a lot. I actually replaced the thermostat today and drained the cooling system, replacing it with new coolant. Seems to have made a tiny difference to the heating inside the car (although it's still only just warm) but not to the overheating problem.

Have checked the oil and there's no water in there thankfully nor was there oil in the coolant.

The reason I asked about the bleed valve is I saw a posting on an American site about replacing the thermostat and there were pictures of a 2002 S40 and a 2000 S40 with bleed valves in different places: neither of which seem to be present on my car!

Not sure what else the problem could be.