[Peter Robi]

Hi all I have a diesel susuki vitara which starting to send me nuts .
It's over heating on the high way , have replaced thermostat, radiator, Radator cap, no leaks , and motor running well .
Any ideas

[Gwagensteve]

What model is it?

Is it a current shape Grand vitara with the renault engine?

Steve.

[Peter Robi]

Yes it is 2010

[fordem]

Define "overheating" - does it boil over or is it the temperature gauge rising in to the red zone?
Does it only overheat on the highway - what happens in heavy traffic or if it's left idling at a stand still?
Do you have a Vitara or a Grand Vitara? What year?

Overheating on the highway would suggest poor circulation, a clogged radiator or similar, but you've already replace the radiator - there have been reports of the JB & JT series Grand Vitaras (2005 onwards) with diesel engines having cooling problems caused by mixing different types of coolant.

[Gwagensteve]

I wonder if the primary problem is overheating or if the overheating is a symptom of something else like a head gasket or EGR failure?

Is it throwing any trouble codes?

You haven't mentioned checking the cooling fan for function - has that been done?

[losfer]

cooling fan has very little to no affect on cooling at highway speeds , airflow over the radiator at highway speed should be efficient .

I would be primarily looking at an airlock in the cooling system . The F9Q has an almost impossible to reach air bleed nipple on the back of the engine. most people dont even know about it or can even find it when they know about it. considering the cooling system has been emptied to replace the thermostat and radiator id be guessing this first. you have to stand at the left hand guard facing the rear of the car , with your left hand you reach to the rear of the motor on the thermostat housing where you will find something that feels likes a tyre valve cap , undo that while filling the overflow bottle until no air comes out.

Secondly, unless you have replaced the genuine suzuki coolant with the same compatible suzuki coolant or flushed out the old coolant thoroughly before adding an aftermarket coolant , i would have concerns that you have blocked up a brand new radiator.

[Chop]

Before buying mine, I had read about a few people having issues with overheating in the diesels. But was told by a suzuki mechanic the same as what Losfer has mentioned above that people mixing coolants in the diesel and 2.4 models caused the most issues. And that sometimes the wrong thermostat is issued.

Do you have a bull bar and or spotties up front blocking airflow?
I have a scan gauge II on my dash so I can monitor mine and mine runs a lot warmer since my bull bar was fitted.
It's surprising how much the temperature goes up and down but on the dash factory temperature gauge it doesn't even move.

[fordem]

Chop wrote:

It's surprising how much the temperature goes up and down but on the dash factory temperature gauge it doesn't even move.

That is by design - the purpose of the gauge is to let you know when the engine is cold (below optimum temp), normal (at optimum temp) and overheating - so to speak, a three way idiot light. If average joe were to see that gauge needle climbing whilst stationary in traffic (and you know because of your scan gauge that the temperature does climb), he would probably panic.

[Eddy]

You seem to have checked / replaced everything but the gauge.
That'd be my next test. Make sure that little sucker speaks the truth.