Losing coolant ideas

[bubblebobble]

I have been working on a Suzuki vitara VVT on and off for while.
Vehicle drives fine but is subject to overheating issues.
Let me say I have asked a similar question previously but need some more ideas.
Vehicle has had the following items replaced due to age about 2 years ago, rad,water pump,rad cap, thermostat.
Fans work as the should and temp gauge reads correctly.
I completed a pressure test and all was ok, infact as I type this Iam in the process of doing another.
Iam of the thinking that the head gasket may have failed between a water way and cylinder albeit very slightly.
Car has no noticeable white smoke or any smoke at all.
Any more ideas as Iam kinda running out of patience.
Tha ks

[Dooheid]

You've done everything I would have done. Are you certain it "is" actually overheating? What's telling you, the gauge? Or is it blowing off steam & boiling?

The 2 possibilities are faulty gauge/sensor or faulty cooling fan. If electric, check the thermo switch and even test the fan itself.

If it's an engine driven fan, it's possible the thermo clutch is gone and the fan is slipping under power. The ram air effect at speed will allow cooling while the water pump is driven, but at crawling traffic speeds, there's very little help in cooling if the fan isn't workin.

[GreenV8S]

bubblebobble said:

Iam of the thinking that the head gasket may have failed between a water way and cylinder albeit very slightly.

A block test aka sniff test would tell you definitively.

What are the symptoms?

[bubblebobble]

ok, too answer some questions and after re evaluating everything and having a chat with the other half who drives the vehicle a few more points.

Sniff test was done - negative for gases -i.e. no colour change of fluid.
Vehicle was still overheating after all the new part changes - i.e. it spat out coolant, the gauge read correctly as this happened, only on long journeys.
It did have a new temp sensor.

Did another pressure test and this time found a small metal pipe which linked the waterpump to the block was leaking ( corroded ).
Replaced the pipe and Orings along with accompying gaskets that were disturbed to get to said part.

Pressure test all good, sniff test all good.

Vehicle hasnt spat out coolant after the coroded metal pipe was renewed however if it goes into red on the gauge she will pull over and let it cool down, check the coolant ( cap off ) to find it needed to be topped up - maybe 2 litres.

It is losing coolant over a period of time ( maybe 1 month max ) which is resulting in the overheating but is being mitigated by pulling over and letting it cool down etc as above.

[GreenV8S]

You need somebody to take a look at the car who understands how cooling systems work. In particular you need them to check whether the radiator and engine have been bled properly. There are various places where an air lock will substantially reduce the cooling capacity without any other obvious symptoms.

[PaulKemp]

I would suggest that the corroded pipe and loss of coolant has overheated the car on a number of occasions and finally the head gasket has let go, probably not in a big way but enough to loose coolant steadily. You could put some gasket sealant in as a temporary fix to see if that stops coolant loss but this can only every be a temporary fix.
The big worry is that the head has warped but you won’t find that out until the head comes off.