2004 nissan ti pathfinder overheating ....... need advice!

Ummm is the Nissan a Auto ? has it got a transmission cooler ? where you towing in a high gear??

Cheers.

Nissan is auto. We turned overdrive off whenever we were towing uphill. It was only overheating on hills ........ We also found it was hotter on gas, so switched to petrol on hills - but was still overheating .........

Yeah - we thought the cost of fan n thermostat was high too .......... too late to do anything about it :-(

Thanks for your reply.

Radiator cap was tested by a mechanic en-route - intend to have that retested.

No coolant leaks (Nissan tested that). I'm assuming Nissan also checked hoses.

Will check transmission at your suggestion (thankyou) .......

Would be real nice if we could find something obvious!

Brakes were off, but we'll check as you say.

Are you suggesting to keep O/D off whilst towing at all times?

Thankyou for your help!

Had similar problems with a statesman towing a large tandem, fitted a larger radiator and transmission cooler, it helped but still had trouble when towing on 40deg + days.

Peter

Viscous fan & coupling were faulty & replaced, as well as thermostat. But still hasn't solved the overheating issue ......

Genuine coolant in radiator.

Your thoughts re a larger radiator mirror my suspicion - that it will more than likely mask the 'real' problem .........

Thanks for your suggestions.

You dont look for hot spots if overheating

YOU LOOK FOR COLD spots which are obviously blocked and have no hot water running through it
Remember to disconnect the electric fans on the back before putting hands in.

Dont try the front Thats usually the aircon condenser.

Yes I never tow in OD my vehicle ran 100deg hotter than in 4th at 90kph on a FLAT road.
Also some ( Toyota especially) temp gaugesDONT MOVE until its nearly too late.

Dont know about yours.

A friend destroyed the radiator in his Challenger by putting an incorrect type of coolant in.
Non compatible, and the two together formed a gel and blocked the core.
It was not a complete refil, only a topup.

I believe that with Toyota it is absolutely essential that only the genuine red Toyota coolant be used otherwise disaster.

Good luck with you endeavours.
mike

Mike,

Thankyou for your follow up - we have been super careful with the coolant - only added water (emergency situation - no coolant on board!) during the loooooong trip to Echuca.

Nissan, of course, added the correct coolant.

NRMA mechanic warned us about incompatibility between differing brands - he topped up with water - they can't possibly carry all brands of coolant in their vehicles.

The only disturbing thought is that the previous owner could have used the incorrect brand ..... hopefully not!

Ditto above I assumed you had the viscous coupling replaced but on re-reading your post maybe not - if the coupling is faulty that will cause the problem Cheers Kev

Also has the vehicle had a new muffler or exhaust fitted??? A faulty muffler or partially blocked catalytic converter will have you scratching you head for years if this is the problem.. Michael

As stated earlier I would be finding another mechanic. It seems he wants to scare you into getting more work done... some of it which may be unnecessary.

from what you describe, it sounds like your rad core is either internally, or externally blocked.

Works fine in most conditions, but put that bit of extra load on it, and it cant cope and exchange the heat created.

First thing to do is to make sure the air con condensor is not blocked full of grasshoppers/ leaves etc, and then check between that and your rad core, often the bit between the two can become full of debrits.
Even a garden hose to back flush from the engine side forwrads thru the core can move a bit of stuff.

If your water pump is not leaking, nor the shaft wobbly, leave it be for now.
Basic check of the rad cap will show if its allowing the system to stay correctly pressurised, thus increasing the boiling point of the system, however if the engine is creating heat, and the cooling system is not dealing with that heat, then look for the bits that exchange that heat.
I am surprised that they didnt do a basic co test of the cooling system, that will show any sign of combustion gasses entering the cooling system, but often when this happens, other symptoms occour that you have not mentioned yet.

Other things to observe are the workings of the fan viscous hub, and ensure the fan shrouds are correctly fitted, and not allowing air to be dragged in from the wrong side of the radiator, thus loosing cooling efficiency.

Its called a cooling system, as there are a few parts that make it a whole, and one or more with a fault can cause issues.

When I had my garage, with what you describe, blockage of the rad is the first thing I would have looked at, along with cap operation, and a co test.

Even a good looking radiator, if its 20 or 15% blocked internally, can cause the symptoms you describe.
Worth the coin to remove rad, and remove tanks, and do a proper cleaning job.

Hope this helps

Trains

Ben & Trains,

Thankyou for your continued suggestions & helpful advice.

We have been in contact with a radiator specialist and will most likely book the car in with him to properly clean & flush the radiator (he said he would remove it to give it a thorough clean).

He also said that if the cooling system is in working order (after all this has been done), and we still have problems with overheating - the next step would be to suspect the head gasket (noooo!) - we, of course, are hoping there will be no 'next step'.

Thankyou again,

Lenita

Also
I should have mentioned the bottom rariator hose.
They usually have a wire coil inside them to stop them collapsing, when you accelerate. When you accelerate, the water pump sucks, and that in turn will collapse the hose, if the wire coil, is not up to standard.

It's also adviseable to check the radaitor cap, the water pump, and the fanbelt, in the process.
Cheers
Again

Thankyou for your helpful hints Bucky.

Car is now in for more analysis on the cooliing system & repairs as necessary. We have also found the water pump is leaking, so will be replaced too.

Hopefully our woes will be over after all this .....

Cheers,

avidcamper

Hi AvidCamper.

Glad they found the pump leaking, I take it that it was only a slight leak.
I wouldnt expect it to cause your overheating, unless it really failed.

One thing to consider, people have been caught out with issues introduced to their cooling system by fitting an aftermarket water pump.

Most are good, and fit correctly, but some have been caught out with incorrect impeller depths, or designs not quite good enought, and have had problems.

When I did mine, I fitted a genuine water pump for this reason.

Over the years I have fitted 100's of quality aftermarket pumps and not had any problems, but after reading on here that some had problems, I chose to go genuine.

Something to consider anyway.

And a Co test should be done before they drop the coolant/ start work on your vehicle, it dosent take long, and can give an indication when tested against a freshly filled system just run/ air bled from system.

My hope is that the core will be up to 15% blocked, and possibly the external by a similar amound due to debrits between rad and condensor.
And there is nothing else

Hope im right :).

Trains

Sorry, what was the cause of the overheating? Was it just the faulty water pump?

Seemed to be a combination of things including viscous fan & coupling, thermostat, water pump. Finally also followed mechanic's advice (endorsed by Nissan) & replaced the radiator with a heavy duty one. The standard one does not give much margin, so if towing up a long, slow hill can fail to keep everthing cool enough. Also installed a lower temperature thermostat which then means the viscous fan starts doing its job sooner ....... all helps!

I am no mechanic, but I think I've gained a bit of an understanding about how all this works now!

Nissan also said if we still have problems, the next step would be to clean the aircon condenser since it could be blocking air to the radiator. Hopefully that won't be necessary - this whole exercise has been quite costly :-(

Cheers

So Nissan knowingly install a radiator which is not fit-for-purpose??? Now that's just cheap...

One would hope the engineers and bean counters spec/install components that do the job, i.e tow.

I assume the thermostat you referred to is inside the viscous fan because the normal thermostat is in the cooling system attached to the engine block so is independent of the fan. Unless how does the radiator influence the viscous fan?

Ben,

Now you're asking questions I don't know how to answer! I can understand when it's explained to me, but to try & pass it on to someone else is another thing entirely.

My understanding is that the lower temperature thermostat will start the viscous fan earlier which will then assist in keeping the engine cooler (?????).

I can't give a technical explanation - sorry - whilst I'm learning, I am not a mechanic ...............

Cheers