Overheating in 4wd mode

I made earlier a topic on overheating during sanddriving and I decided to do a coolant flush. I also found that the spring in the cap wasnt working so replaced that.

Today I went to duck creek road (awesome place!) And was driving on gas in 4wd mode (4h). Half way we stopped and the coolant was boiling and coming out the radiator while the temp gauge never moved. After cooling down, the car didnt start right away. I decided to continue on petrol, it was only a couple more km till the end but in the end the coolant wasnt boiling so not sure if it was the gas mode or coolong. The engine still didnt start at once while I now start at petrol mode. The gas system is checked in oktober 2013 when I bought the car.

Another thing I noticed yesterday that the car the first 5min didnt had much power when I was driving on gas but I thought it was just a cold engine so not sure if this is related.

From this it might be good to get the cooling and gas checked out. My scare obviously is a high bill, in addition i am not learning much if i just bring my car to a mechanic. Because i will do a big lap, i like to be able to solve as many problems by myself as possible. so I am wondering if anyone on this forum from around brisbane has any experience that might be useful for this and like to help me out (a cold beer will be waiting).

Some details: nissan patrol gu, 1997, auto, 4.5l lpg/petrol, last service in oktober 2013, coolant flush and change month ago

Dod you do the coolant change yourself? Are you sure it was fully bled of air? Interesting that the gauge did not show hot yet it boiled? Does the gauge function normally?

These cars are shocking for bleeding properly and it is advised to jack the front of the car up to allow for air to escape.

Sometimes it can take a couple of days of allowing the car to cool right down and then the next morning topping up again.

It is hard to explain about warming up the car with the cap off and when the thermostat opens the level will drop , you then rev the engine up and fill with coolant then quickly close the cap.

The gauge was showing hot when I was sanddriving. My driveway is steepish so I did the rev wo cap thing to bleed for air. But not 100% sure it is done properly. Having said that, the sand issue was before I did a coolant flush so I read that as that the cooling issue isnt coolant related.

The 4.5 has a bleeding point on the heater hoses on the firewall which make them easy to beed out. Only problem is you will need to bleed the converter then heater to get all the air out.

I would recommend having the gas mixtures checked to make sure they are within the specific tolerances ( roughly 2.5% Co2 ) on a gas analyzer, that should solve the lack of performance also check the timing. Incorrect timing and fuel mixtures can cause an overheating fault when the motor is pinging / pre igniting but is rare. Unless you have a stoichiometer of a gas analyzer you won't be able to adjust the fuel mixture on lpg.

When you flushed your cooling system did you have the tanks removed and the core cleaned out of did just reverse flush it with the hose?

So does it over heat??? when you say coolant comes out the radiator does it fill the overflow bottle??

Does the temp rise and fall quickly or does it get hot and stay there... if it fills the overflow bottle does it suck it back after it has cooled???

I didn't remove anything. Just flushed it with water through the radiator followed by coolant. I am not experienced enough to take it apart.

The coolant in the overflow tank was boiling and steam came out of the radiator (I guess because it was to hot to open the bonnet, but green liquid was around the cap after cooling. The coolant stopped boiling after 20min or so. So far it only happens in 4wd mode, slow driving and on gas for sure, petrol unsure. Radiator is so good as new. The fans are on as well during driving.

I am unsure what the lpg inspection is when you buy a car 2nd hand (as part of rwc).
Maybe I should get that checked out if that only can be done by a mechanic

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Originally Posted by dannypatrol

I didn't remove anything. Just flushed it with water through the radiator followed by coolant. I am not experienced enough to take it apart. The coolant in the overflow tank was boiling and steam came out of the radiator (I guess because it was to hot to open the bonnet, but green liquid was around the cap after cooling. The coolant stopped boiling after 20min or so. So far it only happens in 4wd mode, slow driving and on gas for sure, petrol unsure. Radiator is so good as new. The fans are on as well during driving. I am unsure what the lpg inspection is when you buy a car 2nd hand (as part of rwc). Maybe I should get that checked out if that only can be done by a mechanic

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The lpg is inspected for leaks and for correct operation and to make sure the tank is within its 10 year safety inspection during a rwc check.

The radiator has to be taken to a workshop to be cleaned because of special tools needed to re connect the tanks aswell as new seals after it is pulled apart.

Firstly you need to make sure you don't have any water leaks, without a pressure tester you can inly do this by monitoring the water level and a visual inspection of all the hoses and fitting and also on the cylinder block around the welch plugs.

Which fan are you talking about ?? The viscous fan on the motor or the electric one for the A/C? The electric thermal fan should only come on if the a/c is on OR if the engine coolant temp is 96* or higher as a back up, NOT ( normal operating temp) is around 90*C.

To me imho it sounds like you have a circulation fault, be it the radiator cap allowing the water to fill the overflow bottle when it expands but not return which over time will make the water level become lower than the tank and not allow it to circulate, a partially blocked radiator, stuck partially open thermostat or a viscous fan clutch fault because it only overheated when you where laboring the motor at slower speeds in 4h.

If there is a water leak the gas converter will freeze over and stall the motor because the coolant is used to heat up and vaporize the lpg.

A test you can do yourself is, start the motor and raise the idle to about 1500 - 2000 rpm by holding the accelerator cable near the throttle body. If the viscous fan is working is should make alot of noise and make alot of wind for up to a minute then not blow as hard. After that let the motor idle until it is at not and race the motor again, you should hear it engage and disengage. That test will point point us in the right direction to eliminate your fault. The other test will most likely need to be done by a mechanic.

Please try and be specific so we can get a better understand of whats going on with your motor so we can help you out the best we can

When was the last time the Valve clearances got checked ?

Thanks everyone for helping out! This is my first car so I am a noob on many specifics but will look into it to answer all questions so that we can maybe target it to a more specific problem.
I just checked the radiator coolant level and it was too empty. I topped it up with 5l of coolant. Not sure if it was an airbubble or I lost 5l of coolant out of the radiator. The overflow is a bit fuller so it might as well be that a big part of the coolant went into there. I follow the coolant procedure as noted in the manual.

With the fan, I ment the fan on the inside of the radiator. I will do the test tomorrow Alitis007

I bought the car in oktober 2013 and didnt check the valves, I will have a look at the logbook.

If you had to put 5lt in I would say the car was not bled properly as that is a huge amount to lose?????

The cooling system capacity is roughly 12 ltrs and the overflow bottle holds around 2 ltrs, if you lost 5 some of that could have been pushed out when it overheated. I hope you haven't cracked the head driving it around with no water in it but time will tell. Fill the water up and test for leaks how i said in my previous post.

If the water level was half way down the viscous fan wouldn't have worked because it uses the ambient heat from the radiator core to expand a coil to creat resistance to make it engage but you should have heard the a/c fan working trying to cool the motor.

By specifics i meant every detail of your fault because we cant see your car! Being 5 ltrs down is an important detail which you left out in your op but thats why we're all here to help you learn about your car and to try and diagnose its faults.

How can I check if the head is cracked?

Mate when you did your coolant do you know how much you put in????

5lts is a lot and as George has said you need to be specific as to the details..

Some of your descriptions are vague and needs more input..

Try to give as much info as possible as it is hard to understand whats going on from the other side of the keyboard.. cheers

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Originally Posted by dannypatrol

How can I check if the head is cracked?

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First find out where your water is going. You need to have a process of elimination before you jump to any conclusions.

I'm no mechanic , but could it be the radiator is blocked externally , duck rd is fairly steep in the first couple of kms , so maybe the lack of air flow at low speed was a issue ( I use low 2nd 3rd on the climb ) after that its pretty easy going and your in the rain forest so moving quicker in cooler air . Like I said I'm no mechanic , but it seems you only got hot when climbing

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Originally Posted by Bloodyaussie

Mate when you did your coolant do you know how much you put in????

5lts is a lot and as George has said you need to be specific as to the details..

Some of your descriptions are vague and needs more input..

Try to give as much info as possible as it is hard to understand whats going on from the other side of the keyboard.. cheers

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Sorry that my descriptions are vague, it is simply coz I am new to car engine stuff, it isnt unwill. I want to learn more about it and solve it myself instead of just bringing the car to a mechanic.

Re the amount of coolant. I put around 11l in when I flushed it.

I will try tomorrow to diagnose it further, just have to find the accelator cable. Hope that will pin point the problem better.

In the morning i'll take a few pic and post them for you to show you where to bleed from and where to accelerator cable is.

11l sounds about right because the heater core would have had water in it aswell as the block.

Quote:

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Originally Posted by Alitis007

A test you can do yourself is, start the motor and raise the idle to about 1500 - 2000 rpm by holding the accelerator cable near the throttle body. If the viscous fan is working is should make alot of noise and make alot of wind for up to a minute then not blow as hard. After that let the motor idle until it is at not and race the motor again, you should hear it engage and disengage. That test will point point us in the right direction to eliminate your fault. The other test will most likely need to be done by a mechanic.

Please try and be specific so we can get a better understand of whats going on with your motor so we can help you out the best we can

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I drove yesterday 50km motorway on petrol without any issues (I had to go somewhere).
Today I have time to have a closer look. I am not sure where the viscous fan is but starting the engine and raising the idle to 2000rpm result in a weird additional sound, like a fan that is out of balance, but the sound isnt massive, just a bit of side-effect. I cant remember the engine sounding like this when I changed the coolant. There is more of a tsjook-tsjook sound which stays for longer then a minute. After turning the engine off and waiting for couple of minutes and turning it on again, the tsjook-tsjook sound doesnt start right away, it starts a couple of secs after raising idle.
I started both times the engine on petrol.

Quote:

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Originally Posted by gaddy

I'm no mechanic , but could it be the radiator is blocked externally , duck rd is fairly steep in the first couple of kms , so maybe the lack of air flow at low speed was a issue ( I use low 2nd 3rd on the climb ) after that its pretty easy going and your in the rain forest so moving quicker in cooler air . Like I said I'm no mechanic , but it seems you only got hot when climbing

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Problem seem indeed to occur only with slow speed 4wd driving. I was using 2nd gear though.
Losing power on LPG was only when I just started the engine and for the first 5min or so (climbing two hills of aprox 500m). Never had this before. The cooling issue boiling coolant) both occurred using LPG, in 4H mode at very slow speeds (on beach and on duck creek road).

Check the condition of the white plastic fan at the back of the radiator,
they have a habit of becoming brittle .

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Originally Posted by threedogs

Check the condition of the white plastic fan at the back of the radiator,
they have a habit of becoming brittle .

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It seems solid, only bit dusty. It is hard to spin though but that might be normal? The black elastic band that spins the fan looks a bit brittle but it seems to work fine during operation

Sorry mate forgot to get some pictures for you but leave it with me!

That "black elastic thing" is a fan belt and if its cracked you should replace it asap because that not only drives the fan but also the alternator and water pump. There should be 4 all up, 1 for the powersteering pump, 1 for the air con compressor and 2 for the alternator/water pump.

If your a/c on ?? The a/c compressor's clutch clicks like that when it engages but a noisy idler bearing can make that noise aswell. See if you can take a video and post it here so we can listen to the noise??

Quote:

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Originally Posted by dannypatrol

The black elastic band that spins the fan looks a bit brittle but it seems to work fine during operation

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Sorry. That made me laugh. Quite hard.

Quote:

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Originally Posted by Alitis007

Sorry mate forgot to get some pictures for you but leave it with me!

That "black elastic thing" is a fan belt and if its cracked you should replace it asap because that not only drives the fan but also the alternator and water pump. There should be 4 all up, 1 for the powersteering pump, 1 for the air con compressor and 2 for the alternator/water pump.

If your a/c on ?? The a/c compressor's clutch clicks like that when it engages but a noisy idler bearing can make that noise aswell. See if you can take a video and post it here so we can listen to the noise??

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no worries. Both times when the engine overheated, the aircon was on and suddenly stopped cooling, something i forgot to mention. But for the test and for the video, the AC was turned off.
video:
http://youtu.be/-lYj0HYrddc

Where are you located mate?

No one has mentioned anything about the auto side of things. What sort of condition is the oil? Do you know what the flow is like through the cooler section of the radiator? Also are all shrouds, splash guards and the rubbers between chassis and body in place and in good condition?

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Originally Posted by nissannewby

Where are you located mate?

No one has mentioned anything about the auto side of things. What sort of condition is the oil? Do you know what the flow is like through the cooler section of the radiator? Also are all shrouds, splash guards and the rubbers between chassis and body in place and in good condition?

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I am south west of brisbane.
Tbh no idea about the oil and flow through the radiator. I can check the dipstick but not sure to distinguish between good and bad oil.

The splash guard at the wheel on the passengersite is a bit lose. I havent done any mud driving yet, only beach and duck creek rd. Washed the car both times afterwards. Dont know about the previous owner but several ppl told me the engine looks very clean for its age. Obviously that might be just the outside....

How far south west of Brisbane are we talking?

Indoorophilly area

Quote:

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Originally Posted by dannypatrol

no worries. Both times when the engine overheated, the aircon was on and suddenly stopped cooling, something i forgot to mention. But for the test and for the video, the AC was turned off. video: Video Link: http://youtu.be/-lYj0HYrddc

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When the coolant temperature goes over 96*C the a/c clutch disengages to take some load off from the motor to try and not heat it up any further.

From the video i could hear your fanbelts were noisy because they are dry and cracked ( i think you said they were cracked) and just hear a noisy tappet but ever so slightly which is nothing to be alarmed about.

At a guess, in my opinion i think you may have a partially blocked radiator because your fault is similar to when my radiator was blocked. My temperature never moved from where it normally sits unless i was driving thru steep hilly roads or off road where the motor was put under heavier than normal loads. On normal roads i would hear the a/c thermal ( electric) fan come on even if the a/c wasn't on but also if i drove for longer than 30 mins i would hear the water in the radiator bubbling when i turned the motor off.

If you have told us everything thats what i think it could be. Its not hard to remove the radiator ( it shouldn't take more than 30 mins tops!) but you will need to take it to a radiator shop to have the tanks removed and the core cleaned. It shouldn't cost more than $150 so call around first and see who will be the cheapest.

Quote:

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Originally Posted by nissannewby

Where are you located mate? No one has mentioned anything about the auto side of things. What sort of condition is the oil? Do you know what the flow is like through the cooler section of the radiator? Also are all shrouds, splash guards and the rubbers between chassis and body in place and in good condition?

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The fan shroud and associated covers will cause the temp to stay slightly higher but not cause it to overheat. If the auto trans cooler was blocked thevauto would be slipping and or thre auto would have blown

Quote:

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Originally Posted by Alitis007

When the coolant temperature goes over 96*C the a/c clutch disengages to take some load off from the motor to try and not heat it up any further.

From the video i could hear your fanbelts were noisy because they are dry and cracked ( i think you said they were cracked) and just hear a noisy tappet but ever so slightly which is nothing to be alarmed about.

At a guess, in my opinion i think you may have a partially blocked radiator because your fault is similar to when my radiator was blocked. My temperature never moved from where it normally sits unless i was driving thru steep hilly roads or off road where the motor was put under heavier than normal loads. On normal roads i would hear the a/c thermal ( electric) fan come on even if the a/c wasn't on but also if i drove for longer than 30 mins i would hear the water in the radiator bubbling when i turned the motor off.

If you have told us everything thats what i think it could be. Its not hard to remove the radiator ( it shouldn't take more than 30 mins tops!) but you will need to take it to a radiator shop to have the tanks removed and the core cleaned. It shouldn't cost more than $150 so call around first and see who will be the cheapest.

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Cheers! I got a new fan belt just have to look up how to replace it.
I hope you are right about the blocked radiator. I have only heard the water boiling those two times. I will keep my fingers crossed that it isnt a cracked head