Coolant overheating (keteling)

[rhamps]

After a long run in my car whe nyou stop i can hear a boiling sort of noise im thinking this is the coolant overheating and i am guessing that my thermostat might not be doing its job so just ordered new one. Any more ides would help though.

[Lewis Jay]

Its normal.

So long as your car doesnt overheat and gets up to temperature o.k. I wouldnt worry mate.

Lewis.

[Smithmyster]

Id say its totally not normal

Mines never done it in 6 years untill the last 2 weeks,
now the head gasket has gone.

I think your wise to change the thermostat, maybe check coolant blockage and drain / change the whole coolant. Its not worth risking ignoring.

[Bobby (aka Shaggar)]

I'm now on my second Tubby and both do it mate after any extended driving period buddy. From what I can see it's hot water gurgling back up sections of the pipework mate.

Not dismissing the other guys head gasket porbs however it is a trait of MR2 tubbies.

B

[JJ]

Change the thermostat..... This will resolve 95% of your problem...

Theres a channel of coolant around the block that is controlled by the thermostat... when the thermostat opens, it shuts this channel and diverts all hot coolant to the front, otherwise it'll circulate it around the block.

What often happens, these cars are b@stards.. when the thermostat fails or begins to fail, it can fail shut.... so overheats the block....so its regulating 86+ degrees instead of around 82... Its opening far more frequently below 80 degrees to maintain 82, where as, a stats thats on its way out is beginning to open at 86+... buts it not opening far... so theres not a great deal of displacement happening....

Add this to your block retaining the heat till the thermostat is opened = coolant boiling regular...

Get the correct thermostat as well.. many discount parts places catalogue the wrong thermostat.... so be sure its like for like, should be quite long.. and you'll see the valve that it closes off on the block when the stat opens ....

If you fit a short thermostat, the engine will have boiling issues as the coolant wont be diverted naturally to the front.....

[willfinch36]

My turbo is having the same issue, have ordered a new thermostat!

[Charged]

Mine does it after every spirited drive and has done for 3 years.. but I am using a Mk1 cooling system with a Mk2 Turbo engine.

[JJ]

Sorry, just to add... like Ollie after a spirited drive, its quite normal for some kettling, this is the coolant around the turbocharger that boils off and displaced... but this should only be a marginal noise.....

Its also a sign to all of you turbocharged hooligans to let your turbo cool down and run your engine for a few minutes before shutting it down....

[Bobby (aka Shaggar)]

Sorry, just to add... like Ollie after a spirited drive, its quite normal for some kettling, this is the coolant around the turbocharger that boils off and displaced... but this should only be a marginal noise.....

Its also a sign to all of you turbocharged hooligans to let your turbo cool down and run your engine for a few minutes before shutting it down....

Hmmmm, thanks for that JJ. But like I said my first turbo did this for 8 years and never had an over heating problem. The new one (before the engine swap) also did this. Not neccesarliy always after hard driving more after extended drives so after say its been held on the motorway for 2 hours constantly or Ive been stuck in traffic for hours so not neccessarily using the turbo.

Very informed read thogu. Hmmm

[easty-5]

My turbo is having the same issue, have ordered a new thermostat!

what size did you get? 56mm or 64mm?

[rhamps]

My turbo is having the same issue, have ordered a new thermostat!

what size did you get? 56mm or 64mm?

If you still have a rev3 turbo its 64mm well thats what i have got but to be honest i havnt fitted it yet.

[dantheman]

depends on the noise. boiling sounds worrying. if it sounds more like a distant gurgle then its probably the sounds of the coolant being sucked back in from the expansion tank.

[Blacklightning66]

if you actually listen where it comes from , its coolant in the metal pipe work around the turbo charger and the metal water outlets below the filler.

When you shut down the engine, your stopping coolant flow around the engine (you dont say! ) the cooant in these pipes start to boil and gurgle and head up to the filler neck.

if you slowly release the pressure and pop the cap off you can visably see what is going on.

Nothing wrong with the Headgasket or the Stat.

Believe me, when your Gasket or stat goes you will know, you coolant will bubble all the time when the gasket is gone (from cold witht he cap off) and the car will dump its load all the time. (I've changed my stat and gasket 2 times in 7 years of tubby ownership - by my self)

Stats tend to stick open, not shut. Stats work on the principle of the wax core melting as the temp increases - as the temp increases the wax melts and the spring tension on the wax piston opens the stat.

Id say you have no problems at all

[Bobby (aka Shaggar)]

if you actually listen where it comes from , its coolant in the metal pipe work around the turbo charger and the metal water outlets below the filler.

When you shut down the engine, your stopping coolant flow around the engine (you dont say! ) the cooant in these pipes start to boil and gurgle and head up to the filler neck.

if you slowly release the pressure and pop the cap off you can visably see what is going on.

Nothing wrong with the Headgasket or the Stat.

Believe me, when your Gasket or stat goes you will know, you coolant will bubble all the time when the gasket is gone (from cold witht he cap off) and the car will dump its load all the time. (I've changed my stat and gasket 2 times in 7 years of tubby ownership - by my self)

Stats tend to stick open, not shut. Stats work on the principle of the wax core melting as the temp increases - as the temp increases the wax melts and the spring tension on the wax piston opens the stat.

Id say you have no problems at all

[JJ]

Without debating about it... it all depends on how much kettling is occuring, a failed stat can remain closed too... understand the wax coating etc.... but I've had a stat thats failed to open at the correct temps ( temp gauge doesn't reflect ).. .I've seen mine sat at 92 degrees and not reducing, gauge starts to respond / increase from around 96+ degrees....I can name 2 others, 1 an MR2 turbo and one a Celica GT4, so it isn't uncommon in my eyes if the experience has been first hand.... 1 believe or not was a brand new stat from toyota which was taken back.

Most wont realise this high stat temp as the dash gauge doesn't quite reflect the actual circa temp.

As mine sat borderline below boiling, it was only when shut off, you could hear the static water begine to part boil off the block temp.. and thus kettling noise was dramitically increased...

Again... all greement with the slight kettling, this is all perfectly normal... you do the math... a cool turbo will still be running at 200 degrees EGT's, you stick coolant around the bearing housing at 85 deg circa... it'll boil off till the temp of the cast bearing housing reduces...

[rhamps]

Well i just changed my stat and gald i did the stat came out in two bits so definitly was not doing what it was supposed to be doing. I have yet to see if it stops the excessive kettling next time i get a chance to have a longish drive.


At the end of the day £20 and 5 mins work its worth doing just to be sure.

[GGilbert_MR2]

Sorry to hijack thread.
I've recently started experiencing a problem with my high coolant temps going from between 95 to 135!!!, which is far too high. I have done a data log on the ecu, which brings the rev limit right down.
Car is running 450fwhp on a Link G3 Ecu.

Thermostat & ECT sensor (green end) replaced. Still problems...

Anyone suggest other areas to look?
Radiator fans?

[Steve-O 2007]

I think its normal, I did a 1 hour motor way drive and when I parked up I got a few gurgles (only lasted a few seconds). Water Temp guage sat at 90 deg all the time when running but when you shut the engine off it rises to 100 - 105 deg area as the water has stopped circulating. Im guessing this is what the gurgling sound is. As soon as you turn the engine back on it starts circulating and temp drops to below 90.

Gilbert, I dont think its a Radiator fan problem, My Fans Never used to come on and temp sat at 90deg, I now have the Rad fans on all the time and water temp still sits at 90deg. I think due to all the radiator pipe work / coolant in the MR2 the fans dont realy do much..

[GGilbert_MR2]

I've just invested in a bleeding kit, as i'm convinced its an air blockage in the coolant system restricting flow.

[mr2turbo99]

I think its normal, I did a 1 hour motor way drive and when I parked up I got a few gurgles (only lasted a few seconds). Water Temp guage sat at 90 deg all the time when running but when you shut the engine off it rises to 100 - 105 deg area as the water has stopped circulating. Im guessing this is what the gurgling sound is. As soon as you turn the engine back on it starts circulating and temp drops to below 90.

Gilbert, I dont think its a Radiator fan problem, My Fans Never used to come on and temp sat at 90deg, I now have the Rad fans on all the time and water temp still sits at 90deg. I think due to all the radiator pipe work / coolant in the MR2 the fans dont realy do much..

Mines did exaclty this last weekend on a long drive to Newquay. I was told over on the MR2oc.com that it is perfectly normal. It proper put the frightners on me when i saw the needle go up, but with in seconds it dropped back to just below halfway.