Help out a mechanical idiot!?

[benjj]

Last night when driving I was half certain I saw some steam come up from under the bonnet. Shortly after the temp guage shot up to the top when stationary at traffic lights. As soon as I moved away it came back down again and stayed at the normal temp indicator.

Anyway, I've just been trying to fix a wiper niggle and I read online about an airlock in the system can cause a temp guage anomoly. I popped the top off the radiator and saw this (excuse quality of photo, its pissing down and dark out there still...)



Am I right in thinking that the steam last night was my radiator empying itself of its entire contents!?

[Fume troll]

Unlikely to have been all, but some, yes. Top up the header tank and see how much it lost.

Cheers,

FT.

[benjj]

Thanks Fume, will give it a shot...

I've just read online that I wouldn't expect to see actual liquid in there, the little float is all - relieved!

[mig25_foxbat2003]

Worried me when I first saw it as well... especially as the float on earlier models is a sort of milky cream colour, exactly the same colour as emulsified water.

Steam could be a result of a cracked header tank (happens to E46s a lot), a leaking elbow joint, or possibly a water pump on the way out, none of which are particularly expensive fixes

[john_p]

That looks like quite a new tank, what car is it?
IIRC the float starts off red then gets increasingly yellow with age.
I'd be checking all around the system for leaks if you saw both steam AND the temp going up. Be careful driving it around till you have isolated the cause.

[benjj]

Thanks guys.

The car is a 2001 525iA Sport. I just, and I mean last week, had a Service 2 with the coolant looked at and topped up then.

I've just got to grips with reading the float properly and it is right down, won't go down any further. I assume this was at the right level before yesterday.

I just went out for a short 2 mile drive and after it had got up to normal operating temp it was fine for 60 seconds and then it went right up. I pulled into a layby and with the engine still running it came back down to normal over about 2/3 seconds. I drove it home another mile with no budge in the temp guage. Seems very strange especially so soon after a service.

Should I top it up?

[anonymous-user]

You've either got a massive air lock in the system or a dodgy gauge, no way should the temp gauge move so fast as to only take 2/3 secs to "cool down". Make sure you bleed the system with the cabin heater on HOT, also check the electrical rad fan is comming on (at about 95degC) if it is only "overheating" when the car is stationary.

[benjj]

Ok, problem located but not fixed yet.

I have a leak. It is tiny, just a pinhead in size but when the car is hot and up to pressure it is pissing the entire contents of the coolant out over time.



I've got it booked in on Tuesday to be fixed at my local dealer but was wondering two things...

Firstly could I bodge a fix with some putty/sealant/superglue to stop the leak short term? If so any advice what to use?

Secondly, is the part illustrated above going to be an easy/cheap(ish) fix or will the whole rad need to be replaced?

ps - yes that is a nasty crack on the radiator plastic cover though I've been advised it is no big deal...

[john_p]

Probably best to replace the rad, it's about £130 for the part and probably a few hours labour?
And of course, another coolant change!

Annoying, but they can get a battering so having to replace them isn't entirely unexpected.

Probably try aralditing it up for now, keep an eye on it and Halfords sell 4 litre bottles of distilled water, maybe buy a few and keep them in the boot

[benjj]

Thanks John, appreciated. The motor is going into the garage next week and I'll heed their advice - I guess I'm going to be in for £200 at a main dealer to get it done...?

For now I'll make with the glue! Cheers.

[john_p]

benjj said:

Thanks John, appreciated. The motor is going into the garage next week and I'll heed their advice - I guess I'm going to be in for £200 at a main dealer to get it done...?

For now I'll make with the glue! Cheers.

No, a lot more at a main dealer. Any independent will be able to do it. Labour rates are significantly over £100/hr for main dealers, although you may get a discount .. ring and check!

[benjj]

Man alive, shows how long its been since I've used a main dealer...! I just called and my dealer (Colne, Lancashire) is £115 + VAT per hour.

Am looking for an ini, pronto!