Froffee Coffee? A Cooling Conundrum...

[Bee Elzebub]

Ooopsie! Looks like I've got a 'cooker' on my hands, now, with my 2.7Tdi Maverick...

Took a 286-mile-long drive yesterday, mostly 70mph motorway cruising - the temperature gauge (which normally doesn't go higher than about 20% of its range) started to climb toward half-way; I wasn't worried, just surprised - but when I parked-up at Brooklands Museum & walked around the jeep's front, there was rusty brown water dripping down underneath...

I popped the bonnet - the expansion tank (that's normally always totally empty) was full to its cap with frothy rusty-coloured water, some of it dribbling out of the top vent, all over the electric plugs right behind its mount. Oh, sh*t, I thought - but I got on with my visit, as it'd cost me a lot of aggro to arrange...

Once it had cooled, I topped-up the radiator via its cap, as normal, and toddled off home. The gauge stayed low again until I reached Dartford tunnel, when it started to climb as I sat in the (thankfully short) queue - again, it didn't go over the half-way mark, so I twitched my eyebrows in puzzlement and drove on - but when I got up the A12 around Witham, there was another standing queue from a minor accident...and that's when the temperature really started to climb up. Obviously, it had pushed out enough coolant by then, to start going that high. The power of prayer shifted the queue and off I went; about four miles on, the gauge was back down to about 30-40%, so I just kept going until I got home...and again, there was frothy coffee dripping out of the tank breather.

My guess - is this a clear sign of a blown head-gasket? Or might it be a sign of another cooling problem - say, the viscous coupling on the fan (if this engine has such a coupling)? :nenau

If so, is the swap a difficult one, with the intercooling kit over the engine? Any special tools/techniques required?

Any practical advice most welcome!!:bow

 

[extreme-4x4]

stuck thermostat or blocked rad, easy fix, but if it was me id pop a new rad on too just so you know its clear the old one will be full of crap anyway :thumbs

 

[Bee Elzebub]

Ah! Always the easier option, eh? Typical of me to fear the worst!

I have to admit that I still find the expansion tank idea somewhat strange, when the water can escape to the tank, but not return past the (obviously one-way) rad' cap...

It's just worrying when the 'orrible rusty water fills it to the brim like that; first thoughts go to blown head gaskets, simply because the water's gone from nice clear blue to shite & froth in a very short while, characteristic of combustion gases escaping into the cooling system & cooking-up the water...at least, that's what I first thought, based on a previous motor's problem.

I'll start with a thorough system flush, as I'm skint, then see about swapping the rad...

Cheers for the pointer, though! I'll give it a go!

 

[extreme-4x4]

if your skint just take the thermostat out and see how it goes for a while

 

[kitchenman]

Are you sure you have enough water in the system, the expansion tank should always have water in it

Read the manual about filling with water:doh

 

[Bee Elzebub]

Are you sure you have enough water in the system, the expansion tank should always have water in it

Read the manual about filling with water:doh

Well, that's the other point I was also trying to make - how the hell does the expansion tank system work??? Obviously, water 'expands' into it as it heats & expands in the system - but there's no way it can return, given that the radiator cap works as a one-way sprung valve...so what's the point? The tank can only overflow out of its breather hole, once full; seems a daft idea to me...:nenau:doh (It was empty when I got the motor, and empty it stayed, even after three or four top-ups to the rad' cap level - I assumed that it was normally empty, the same as several other cars I've had in the past...)

Either way, I'll give it a flush-through this weekend & maybe give the radiator some mild caustic clean-out (works great, if you're very careful!), then see how that goes. Given that it's still somewhat chilly, I'd rather just test the thermostat in a pan of hot water and replace it if knackered (they're pennies, compared to a new rad')...

 

[extreme-4x4]

i had a similar problem this week , replaced the rad cap with new . euro car parts 4 quid ish and all fixed

going to change the thermostat as well seeing as i bought the part, now im just stuck with this new water pump i got trade

 

[11redrex]

isn't the rad cap like a thermosat ? Ie, when the water gets hot the sprung valve retracts and lets the pressure off .
? The water then gets sucked back into the system ? Or am I completely wrong ?

 

[rustic]

isn't the rad cap like a thermosat ? Ie, when the water gets hot the sprung valve retracts and lets the pressure off .
? The water then gets sucked back into the system ? Or am I completely wrong ?

You are totally right...

See:-

http://auto.howstuffworks.com/how-does-radiator-cap-work.htm

You must have antifreeze solution in the expansion tank or the water coming out of the rad when hot will turn into steam.

Hope it helps..
Best regards, Rustic

Ps.. Just this minute renewed my membership, so you are stuck with me for another year. :doh


.

 

[extreme-4x4]

the rad cap is stamped 0.9 so im guessing thats 0.9 bar dunno
but yes thats how it works, mine was under a fair bit of pressure so obviously stuck . the new thermostat should be effective too, i was getting water on the floor but thats stopped , so ill probably just shelve the pump for now

ive gone down to an 82 degree thermostat this time , my mav preferred the cooler one

 

[Bee Elzebub]

Yay! Mucho thanksias for the "hedumication", chappies! New rad cap coming riiiiiiiiiight up!!!

Never knew that the cap acted thus - I assumed from its basic design principle that it was a one-way pressure relief item - I just hope all the rusty-coloured water isn't a bad omen if something else going duff...

I'll give it a good flush-out anyway, and treat it to a new cap (the existing one looks relatively new, but it's bin-time, I reckon)... Let you know how it works out, ok? Thanks again, guys!

 

[Bee Elzebub]

Okay - looks like I've sorted this problem: One new thermostat (original was stuck partly open and wobbly/scuffed), one new radiator cap (looked OK, but what the hell...)...and a big flush-out of one very sludge-blocked header/expansion tank! Sheesh - ya should've seen the rusty-coloured sh*t that came out of the bottom two inches of the 'tank - took one hell of a blasting from a hose, and a poke with a sharp stick to stir it out! Don't know where all that sludge came from (probably a long-term build-up, I dare say), but it'd effectively bunged the hose hole, so that hot pressurised water could blow in & up from the radiator overflow...but as it started to return upon demand, the sludge closed up the hole and strangled the return supply. I think...
Anyway - took it for a run to stir the 'airlocks' out, and let it have a good gurgle when I got back. Tomorrow, I'll re-check the level & top-up as req'd...then test it again & let you know...
Many thanks for your input, chaps!

 

[extreme-4x4]

id start saving for a new rad then if it was that crappy:augie

 

[Bee Elzebub]

Didn't need a rad' - I flushed it right out from bottom hose to top, and it holds full quantity, with no leaks (in all honesty, it looks fairly new anyway, so I'd guess it's already been replaced).

Anyway - it's gone to a new home now, so thanks for all the welcome advice on here, chaps - really appreciated it!