Tomtom2012

Having a pew problems with over hearing on my v1 sti first my top rade hose is hot and the bottom is cold will drive fine then temp gauge starts to rise and fall and bubbling our of the overflow tube with yellow cap any ideas hoping not head gasket and was thinking thermostat
Any help guys

ossett2k2

iTrader: (9)

Airlock? Check on here on how to fill without airlocks.
Thermostat? Cheap to replace but you can test yours if you take it out.
Head gasket? Get a sniff test done

DutchKev

iTrader: (1)

Had the bubbling from the overflow on 2 of my classics - sadly was hg failure even after a stat change and a burp. Get a sniffer test done asap

alcazar

iTrader: (2)

As above, sniffer test first.

Had any work done on the cooling system recently?

johned

If it does it more when boost is used it is probably HG.

Tomtom2012

Done a 30 miles drive mixed driving not a problem then starts again feel bottom rad hose and cold top is hot what are chances it's the thermostat

Hawkeye D

The bottom hose will always be cooler as that's the rad doing it's job - putting colder water into the system.
I've just sniff tested my 07 STi, same bubbling. Struggled with sniff test, the detection fluid kept staying blue.

Anyway, gave it a real good boost in 4th and 5th gear, got home, bubbles in the non pressurised overflow tank.

Managed then (just) to get the sniff test dye to turn green, not yellow.
Good enough for me, my HG's or at least one is shot.

Black bits it the coolant, like thin tiny bits. It's the sealant from the HG.

Rebuild time for me!......oh well, a built 2.5 will make a cracking road car, so in that respect I'm pleased that I actually have a good reason to get it done.

Ouchy on the wallet though lol

Tomtom2012

the bottom hose is cold then other times hot so I'm not sure if theremostat is some times not opening

Tomtom2012

Am I right in saying the thermostat is where the bottom rad hose connects to

alcazar

iTrader: (2)

Please............do you READ any replies?


If the thermostat stops working, the WHOLE ENGINE runs cold.

ossett2k2

iTrader: (9)

Yes it's in the waterpump housing connected to bottom hose.

I would of thought if a thermostat is stuck shut it would make an engine run hot not cold?

johned

Did you sort it?.

alcazar

iTrader: (2)

99.9999% of the time they stick open. it's a failsafe thing, so as not to destroy your engine.

A failed thermostat almost always means the engine doesn't reach temperature.

Jeem

iTrader: (1)

Just to say on one of my scoobs someone before I owned it had put it's thermostat in backwards so the constant flow of water pushing against the thermostat eventually jammed it shut, killed my engine