Yaris D4d- Overheating Problem

[elmer121]

Hi guys - advice needed, please ...

Having read the other posts on 'overheating D4D's'...here's my story...

Recently purchased a '52' Yaris with 105K miles on clock...

Bringing home on motorway noticed coolant light flashing.

Got home. checked coolant - OK.

Took it to Toyota specialist garage - replaced thermostat, water pump, radiator & temp sensor.

Fan working OK

Problem still exists - have been advised it could be potential head gasket problem...

My question...

What I don't understand is the engine can run all day around town and red light never comes on.

As soon as I take on open road and 'work' engine - light comes on.

If I slow down - or return to 'town use' - light goes out.

Are these symptons still those of a potential head gasket problem?

If the head gasket is on its way out, as described above - will the engine be less powerful?

Also, what happens when the head gasket 'goes'?

Sorry for so many questions - but you guys are the best at answering them!

Ever hopeful

Alan

[Shappers]

have you checked under the oil filler cap? Is it clean or is there a mayo like substance? That would indicate water / oil is mixing adnd head gasket blown

A compression test should tell you if the head gasket has warped,

[elmer121]

Thank you for the tip...

I'll check tonight.

What I don't understand is - there appears to be no loss of coolant.

I'll get back to yuo.

Thanks once again

Alan

[Madasafish]

What happens when a head gasket goes.

Son has just had one go on Peugeot 106.

Oil everywhere: the head gasket broke at an oil gallery. Hole in radiator : the cause : water everywhere.. not in radiator. :-(

No oil in water or water in oil: but these often happen.. check the radiator for oil - white scum or oil on water.. and check engine oil level - if it is over the limit there may be water in oil.

Oil in water means the cooling system has to be flushed out. Or at worst a new radiator

Water in oil MAY mean nothing apart from a hg or could result in a complete new engine...

In son's case, the radiator had failed and a new hg and radiator were needed.

If an engine has been run without proper anti freeze, it is possible the engine waterways have silted up from corrosion and the engine will overheat on full power as on high speed runs..

[elmer121]

What happens when a head gasket goes.

Hi Madasafish

Thank you for your informative description of an head gasket going!

Errr - I hope that doesn't happent to me!

I have replaced radiator, water pump, thermostat & temperature sensor!

To answer Shappers' point

Had a look at top of oil filler cap - clean as a whistle - no mayo!

Removed rad cap - air gushed out!

Removed cap on reservoir to right of radiator - air bubbled out of this chamber.

Will run car again tonight - Let's see what happens.

Thanks for your help so far...

Regards

Alan

[Raeman]

Hopefully, it's just an air-lock then Alan ;)

[elmer121]

Hi Raeman

Yes, I hope so...

I'll give the car a thrash at the weekend - and report back!

Cheers

Alan

[Rumbly]

Any half decent garage really should have a coolant sniffer, it is a device containing a reactive chemical. Coolant from the vehicle is drawn into the device and mixed with the chemical, if the chemical turns blue there is combustion gasses present in the coolant and the head gasket is definitely leaking, if not then it probably isn't.

The first thing that should be done with any overheating vehicle without a really totaly obvious cause is a sniff test, saves all the messing around and expense of replacing thermostas and water pumps then finding out it's the gasket. The test takes about a minute to do.

[elmer121]

WOW Rumbly - what a fantastic piece of advice!

I did not know of such things - and maybe my garage doesn't either!

I'll get on to them...

The funny thing is I can run around town all day and the flash red light doesn't come on.

If I work the engine at 2,000+ rpm on the motorway for a prolonged period then on comes the light.

As soon as I get off the motorway - drop back to a different driving mode the off goes the light.

The coolant level remais constant in the reservoir.

There is no 'mayo' in the oil filler cap - a check advised in an earlier post.

The fan kicks in and out...

I am at a loss...

I'll follow up on your advice - and report back!

Ok -all for now - and thank you once again

Alan

[Rumbly]

Hi Alan,

Yup a lot mechanics don't know about the coolant sniff test, it really is a fantastic tool for diagnosing blown head gaskets, and not very expensive either.

It's been a while ... 20 years or so .... since I worked at fixing cars/bikes for a living. I used to offer a coolant sniff test to customers even with an obvious cooling system fault. Sometimes if an engine overheats for another reason it damages the head gasket as a result of the overheating ... hillman imps springs to mind ... and doing the sniff test confirms the gasket is still ok .. or not :( . I've sorted obvious cooling system faults then a couple of days later the car re-appears still overheating ... head gasket has gone. For a few quid the customer and garage (this often ends up in an argument of the "you haven't fixed it" variety) gets at least some peace of mind that no real damage has been done as a result of the overheating.

Can't think what your problem could be, mysterious cooling system problems can be a real pain to diagnose .. anything from a faulty sensor to gummed up cooling passages in the engine cos somebody put some horrible gunge in to try to sort a radiator leak, car has been run for ages with no antifreeze and the whole cooling system is full of corrosion. First thing I'd do is a sniff test then take it from there.

Hope you get your problem sorted out shortly and it is something simple.

[elmer121]

Well Rumbly, you certainly 'rumbled' the problem!

I got a 'sniffer- test' done - the blue liquid started to turn yellow.

The guys in the workshop all agreed the head gasket is on its way out - and recommended I change it!

Gulp!

Oh dear, the joys of motoring I suppose....

Off to the garage I go...

Thank you for your help - I really appreciate you 'rumbling' the problem.

Cheers

Alan

[Rumbly]

Hi Alan,

Glad you have the problem diagnosed .... sorry it's the head gasket :( .... not the end of the world though.

While the head is off it's essential that the head is properly checked for warping, it probably won't be warped but MUST be checked cos if it is and it's not skimmed straight you'll just end up with the same problem again.

All the best and hope you get sorted out soon.

[pinkbits69]

I have had the same problem, the gasket is metal so should not be a problem, but, and i am sorry to report that it was a cracked cylinder head. Needs checking as the cost of replacing the gasket will be high and the problem may still exist.

[Raeman]

Hi Alan,

Glad you have the problem diagnosed .... sorry it's the head gasket :( .... not the end of the world though.

While the head is off it's essential that the head is properly checked for warping, it probably won't be warped but MUST be checked cos if it is and it's not skimmed straight you'll just end up with the same problem again.

All the best and hope you get sorted out soon.

Wise words to have the head skimmed.

I once owned a mk2 Golf and the head gasket went. The cost of having the head skimmed was about £40. That was like 10yrs ago now so prices will probably have gone up.

Good luck!

[Madasafish]

When son had his Peugeot 106 head gasket replaced, head was skimmed for £45...

[elmer121]

A big thank you to all the guys/gals who have contributed on the subject of my overheating Yaris.

It is booked in to the garage for Monday 27 July...

I will bring garage's attention to the various points you raised - skimming and cracked heads.

I'll report back sometime next week - hopefully with good news!

Phew!

Thanks & Regards

Alan