Hi all, just a quick question. The other evening I was stuck in traffic and crawling along for over an hour and a half in Portsmouth in the rain. All my dials were running as expected, oil, volts and engine temp were normal. Anyway, I noticed that there was steam coming from under my bonnet.Not a lot and it came and went (if that makes sense)?All the time my temp gauge was normal, not overheating and it was not hot in the cabin. When I started moving the steam stopped.When I got home and she had cooled down I checked the coolant level and had lost maybe 200ml.<o:p></o:p>
My passenger (who has regular breakdowns in her VW camper so knows more than I do about engine death) said it was a little bit of steam.I on the other hand (being a worrier) thought that it was lots; I guess it was like a little stream, like a kettle boiling.<o:p></o:p>
Is this a sign the radiator is on the way out?I have checked for cracks, and found none and the radiator seems to be in good condition, but there is a little bit of water marking by the rad cap hose thing, but not much.I had heard that steam can be let out to reduce the pressure in the system.<o:p></o:p>
I know I should change the radiator as a matter of course but I really don’t want to have to disturb everything, and being an Automatic it will be an even bigger job as the radiator cools the transmission fluid.<o:p></o:p>
The radiator cracks aren’t always obvious until the rad is removed. If there is any kind of wetness on the top of the radiator, replace it. If the radiator cap is failing, it won’t let enough steam out to cause appreciable wetness; instead, you get a tell tale salty deposits around the rad cap.
As the system pressurises, excess should go into the expansion tank. If it over pressurises (head gasket gone), then the expansion tank can overfill.
Don’t want to alarm you, but mine did that just a few bits of steam on wet days in traffic, 2 weeks later the radiator dump all its coolant on the A1 on my way home
As said above, check the rad cap 1st, is the cheapest bit to replace and might be the problem…
It takes a considerable temp rise to affect the temp guage so sadly no indication doesn’t necessarily mean no problem.
OE cores are known to fur up (especially if tap water has been used, I speak from experience ) and this leads to the fractures in the plastic rad where it meets the ali top. You may also hear bubbling in the expansion tank, another sign things are going South.
Good news is rads are reasonably cheap, but with yours being an auto £200 is about right.
Think of it as investing in a bit of engine bay bling…
When I replaced my rad the top of the radiator appeared wet:
But only when I removed the radiator, was the crack visible (on the engine side)
I fitted a £70 pattern part from Autolinkuk; it is similar to OE, but the drain plugs are not interchangeable. Plus, give it a flush with water before fitting, as mine was full of aluminium dust.
Thanks for all the replys, I think I will have to bite the bullet and change the radiator as I have lots of driving coming up. I am hoping this is the problem and its is not something terminal. :(
If you’re not certain it’s the radiator, do check all the hoses first - these are much cheaper and easier to replace! I’ve had several instances of steam from under the bonnet - once it was the t-connector at the side of the thermostat housing, once it was the radiator itself, twice it was just hoses.
That said, if the radiator has never been changed, it’s probably a good idea to change it anyway - my old one was a complete mess (definitely blocked in various places, and finally sprung a large leak along the top) - but definitely check the hoses and metal connections too, I understand that t-shaped one I mentioned is a very common one to rust though. Good luck!
I agree completely, have the car run awhile, till it warms up and see if you have an issue. Even better, refill your radiator with green radiator antifreeze, it improves performance plus…even glows in the dark if it leaks Make sure you run the car awhile before you write off that it could be a hose leaking (high rpm after the car is hot should reveal the problem). Radiator cap, then thermostat would be my next guess…
If you find that the leak is in the radiator there are certain chemicals sold to block small leaks but a radiator change is in order, it will soon give you trouble, and you definitely don’t want to risk your engine running very hot …(or driving around with gallons and gallons of water like I have )
A mechanic can check easily if he uses a pressurising radiator cap, pumping pressure in, will reveal the trouble…
) and this leads to the fractures in the plastic rad where it meets the ali top. You may also hear bubbling in the expansion tank, another sign things are going South.
Make sure you run the car awhile before you write off that it could be a hose leaking (high rpm after the car is hot should reveal the problem). Radiator cap, then thermostat would be my next guess…
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