over heating at motorway speeds HELP
Discussion
I have briefly skim read this.
My take - it's a TU engine therefore it needs a head gasket LOL.
TU engine only exceeded by K series (incorrectly so IMO) in it's reputation for having the worst head gasket failure record in automotive history. If you're contemplating a water pump (and cambelt) change you may as well fit a new head gasket while it's in bits anyway.
Does it have a engine oil leak from the front/drivers side corner by any chance?
My take - it's a TU engine therefore it needs a head gasket LOL.
TU engine only exceeded by K series (incorrectly so IMO) in it's reputation for having the worst head gasket failure record in automotive history. If you're contemplating a water pump (and cambelt) change you may as well fit a new head gasket while it's in bits anyway.
Does it have a engine oil leak from the front/drivers side corner by any chance?
Edited by russell_ram on Thursday 2nd June 13:43
George111 said:
Didn't you have the sniff test done ?
Can't see how it would helphttps://youtu.be/3AlfCOtIRaY?list=PLRe_1TUq_iRPmuD...
Sylvaforever said:
Krikkit said:
It's just tripped by the temperature sensor on the ECU. The gauge is powered from its own sensor.
No it isn't tripped by the temp sensor on the ecu.you either have two sensors or a single double output one
Itsallicanafford said:
so, to update this, its in the garage...
Its not the water pump as they have had that off and it looks OK. Its also not the head gasket, but the heads coming off as they think it might be a blockage in the waterways in the block...
This is crazy. There are no waterways in the block small enough to get blocked in the first place and even if there were it would overheat all the time. The block's just a big open tub. There's nothing in it you need the head off to check anyway. Did they do a proper pressure test? That's the first step. If there's a leak anywhere then the coolant will boil at much lower temperatures than it should and then start blowing out of the vent which you say it does.Its not the water pump as they have had that off and it looks OK. Its also not the head gasket, but the heads coming off as they think it might be a blockage in the waterways in the block...
A pinhole will do it or just a single hose clip with a bad connection.
FordPrefect56 said:
Itsallicanafford said:
so, to update this, its in the garage...
Its not the water pump as they have had that off and it looks OK. Its also not the head gasket, but the heads coming off as they think it might be a blockage in the waterways in the block...
This is crazy. There are no waterways in the block small enough to get blocked in the first place and even if there were it would overheat all the time. The block's just a big open tub. There's nothing in it you need the head off to check anyway. Did they do a proper pressure test? That's the first step. If there's a leak anywhere then the coolant will boil at much lower temperatures than it should and then start blowing out of the vent which you say it does.Its not the water pump as they have had that off and it looks OK. Its also not the head gasket, but the heads coming off as they think it might be a blockage in the waterways in the block...
A pinhole will do it or just a single hose clip with a bad connection.
russell_ram said:
I have briefly skim read this.
My take - it's a TU engine therefore it needs a head gasket LOL.
TU engine only exceeded by K series (incorrectly so IMO) in it's reputation for having the worst head gasket failure record in automotive history.
That's a bit unfair, the Fiat FIRE engine must be very close to if not at the top of the list My take - it's a TU engine therefore it needs a head gasket LOL.
TU engine only exceeded by K series (incorrectly so IMO) in it's reputation for having the worst head gasket failure record in automotive history.
The TU engine are certainly well known for head gasket failure however.
That'll not help by the looks of it.
I am guessing the gasket has been changed before for a cheap one that clearly isn't up to the task of providing sufficient water flow.
Although, in fairness, I look at that & think those holes look very small, but then looking around at new/fresh ones on ebay the holes are all looking about the same size as most of those ones.
There are 3 different sizes in different positions & they appear to all be about the same.
I am guessing the gasket has been changed before for a cheap one that clearly isn't up to the task of providing sufficient water flow.
Although, in fairness, I look at that & think those holes look very small, but then looking around at new/fresh ones on ebay the holes are all looking about the same size as most of those ones.
There are 3 different sizes in different positions & they appear to all be about the same.
Edited by E-bmw on Wednesday 8th June 20:02
Yeah, that's the working theory, they said that even after a few minutes on tick-over the head was getting very hot so they have assumed that there is insufficient flow. But, the correct part would appear to be similar if the image on 106parts in accurate...
A new gasket is coming in tomorrow so they can check to see if the existing one was incorrect...
The waterways in the block and head seem far larger than the holes in the gasket, looks alittle odd?
A new gasket is coming in tomorrow so they can check to see if the existing one was incorrect...
The waterways in the block and head seem far larger than the holes in the gasket, looks alittle odd?
Itsallicanafford said:
Yeah, that's the working theory, they said that even after a few minutes on tick-over the head was getting very hot so they have assumed that there is insufficient flow. But, the correct part would appear to be similar if the image on 106parts in accurate...
A new gasket is coming in tomorrow so they can check to see if the existing one was incorrect...
The waterways in the block and head seem far larger than the holes in the gasket, looks alittle odd?
Not to anyone who understands how engines are designed. The holes in the gasket are sized to balance water flow throughout the block and head to keep all cylinders the same temperature. Until a prototype engine has been built no one knows exactly how big those need to be. The block and head are cast with holes much bigger than needed and the gasket is adjusted during dyno testing with thermocouples placed all over the engine until temperatures are even. It's about the same process as balancing the radiators in a central heating system by adjusting the lock shield valves. The gasket will usually end up with large holes at one end and just pinholes at the other to balance the flow to the cylinders farthest from the pump. I wouldn't expect a garage mechanic to understand any of this but it's room 101 stuff to an engine designer.A new gasket is coming in tomorrow so they can check to see if the existing one was incorrect...
The waterways in the block and head seem far larger than the holes in the gasket, looks alittle odd?
The one thing that doesn't look right is the clean areas on a couple of piston squish bands, especially cylinder 4. It looks like water ingress has been steam cleaning these. Get the head skimmed lightly, it's probably warped anyway by now if it really has been overheating, and the block surface cleaned up properly with an oil stone before rebuilding it.
Dave Baker
Puma Race Engines
Thanks Dave for the response, very much appreciated. My apologies in advance if i use the incorrect terminology below, as you can tell i am a layman when it comes to the internal working of engines!
The mechanic did say that they thought the head gasket wasn't particularly tight when they removed it, could coolant have been passing into each of the cylinders and causing the cleaner areas on the pistons? The car was abit Smokey, if you revved it hard it would puff out a bit of blue/white smoke but i had that down as worn valves seals (which the are going to replace now the head is off) and generally a worn engine as it has done 90K miles. It would be especially bad if you left it to idle for a while and then accelerated.
The head is going away to be checked and pressure tested so i assume that they will skim it if required.
Many Thanks
The mechanic did say that they thought the head gasket wasn't particularly tight when they removed it, could coolant have been passing into each of the cylinders and causing the cleaner areas on the pistons? The car was abit Smokey, if you revved it hard it would puff out a bit of blue/white smoke but i had that down as worn valves seals (which the are going to replace now the head is off) and generally a worn engine as it has done 90K miles. It would be especially bad if you left it to idle for a while and then accelerated.
The head is going away to be checked and pressure tested so i assume that they will skim it if required.
Many Thanks
"The holes in the gasket are sized to balance water flow throughout the block and head to keep all cylinders the same temperature."
And at least one of those in the pictures appears to be blocked? So plenty of flow at low revs, not enough at motorway speeds = local boiling in the head. One of the many common TU failure modes.
And at least one of those in the pictures appears to be blocked? So plenty of flow at low revs, not enough at motorway speeds = local boiling in the head. One of the many common TU failure modes.
russell_ram said:
"The holes in the gasket are sized to balance water flow throughout the block and head to keep all cylinders the same temperature."
And at least one of those in the pictures appears to be blocked? So plenty of flow at low revs, not enough at motorway speeds = local boiling in the head. One of the many common TU failure modes.
I see a bit of gunge in a couple of the larger holes but the pinholes are all fine and nothing worse than hundreds of gaskets I've removed over the years. You can however see where the fire ring is letting go in places. Far more likely the engine over heated once due to lack of coolant, a leak or airlock, started to warp the head and then it's downhill from then on. As I've said before the symptoms here were mainly red herrings. There's no way this engine wouldn't have overheated under hard use at low speed just as easily as at cruise at higher ones. It wouldn't have been until the water level dropped enough though which is why it was fine immediately after filling and showed problems on a longer run. We were misled by the 50 mph thing and not being told it kept venting water. Anyway, lessons learned hopefully!And at least one of those in the pictures appears to be blocked? So plenty of flow at low revs, not enough at motorway speeds = local boiling in the head. One of the many common TU failure modes.
thanks for the responses chaps.
Could i ask a quick technical question. When hot (or very hot as i was looking after a run with rad. fan on) should the coolant be flowing through the radiator? I pretty sure the answer should be yes but if you look into the expansion tank the water is totally static? Would you not see any movement in this coolant in the tank, being the design of this is directly linked to the rad rather than a pipe fed header tank design.
Could i ask a quick technical question. When hot (or very hot as i was looking after a run with rad. fan on) should the coolant be flowing through the radiator? I pretty sure the answer should be yes but if you look into the expansion tank the water is totally static? Would you not see any movement in this coolant in the tank, being the design of this is directly linked to the rad rather than a pipe fed header tank design.
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