overheating?

[vespasprint150]

Hi, not a new problem I believe, but I would need some help in taking a decision here!

1994 TB42 with about 90'000k that has been driven most of its life here in Dhaka city, in a hot, dusty environment with heavy traffic (start and stop all the time).

I suspect the engine is overheating a bit, bcs after 15 minutes or so after starting the engine the temperature gauge is already up to the middle, and after some more time (with a/c on) the temp goes up to 2/3 (no towing or anything).

Went to 2 different workshops and both basically laughed when I suggested to put in an aftermarket temp. gauge... The first one suggested changing the fan engine (?) after a rapid checking; the second workshop suggested to open up the engine block (head), replace the whole head-gasket and replace (?) service the head valves (plus cleaning, flushing etc.); everything for some 700$.... (head valve? 200$, head-gasket kit 50$, valve cover gasket 100$, radiator servicing and cap 30$, spar plug 40$ etc.)

By the way, I get horrible figures, with 2.5Km per liter... (both a/c on, mainly first and second gear...).

Suggestions on how to proceed? Note that Radiator and fan are 3 years old, front a/c has been replaced 6 months ago, engine oil and servicing ever 6 months, new spark-plugs ...

I am totally ignorant about engines, but I love that big truck! HEEEEELP. Are they cheating me or shall I trust them?

Tom

[Clunk]

I unfortunately know very little, so I'm not much use to you mate but first thing I would check is the thermostat............ cold possibly be stuck

[macca]

40litres per 100klm is a lot.
Haven't got a brake dragging, you would smell it I'm sure.
Blocked air intake of filters.
How is the performance?
A coolant system flush and refill with a good coolant wouldn't go astray but that wont make a huge difference to the fuel.
Slow road speed (both a/c on, mainly first and second gear...) will reduce airflow through the radiator, viscous coupling could be an issue.
Be interesting to see what a flush and an electric fan would do.
Ambient air temp might not help as well.
When you say Dhaka is that Bangladesh? Had a great stay there in 1983 when backpacking.
Good luck Tom

[patch697]

Given the driving conditions you've described & the temperatures your doing it in (with the aircon on) im not at all surprised its running a tad warm.

You may be surprised to know that the gauge readings your describing are suggestive its still under 100 degrees/C.

Nissan gauges are well known in Australia for not being very trustworthy so before I'd do to much more I'd have an after market Temp gauge fitted & be sure of whats really going on before worrying yourself & spending on unnecessary repairs.

As for your economy? Its sounds to me that a good drive on the open road wouldn't go astray & give the engine a chance to burn out all that's been built up in it from all that slow stop/start driving.
Being a 94 in tipping its fuel injected & may pay to have the fuel system serviced. A poorly functioning fuel delivery system will rob you of power & send your fuel usage through the roof.


Best of luck.

[vespasprint150]

Thank you Paul and Macca: Performance is good (can acceleration be good on a Patrol?:)), coolant is clean (I dig my finer in the radiator and the liquid is clear) and the coolant system has been flushed 12 months ago or so.

What is a "viscous coupling?" Yes, Dhaka in Bangladesh! Feel free to come over and bring the patrol for a good open driving!

So, if I understand well I should first instal an aftermarket temp. gauge (any suggestion on brands / kinds / web site where to buy?). I actually have a colleague flying to Perth in two weeks time (where I believe it is easer to find spares parts); then (or maybe at the same time) do a good flushing and install (or replace) the electric fan, right?

For the model, first registered in '94 but it is still a carburetor model: air filter is new, oil filter and fuel filter also new, carburetor seems to be nicely tuned and spar plugs are not even 6 months old. Any goo trick to reduce fuel consumption?

Another thing: the circuit panel of the driver electric windows doesn't work properly (I have to bang on the door to make the electric engine work..): is this available on the spares part market? Couldn't find it on the web-sites listed in this forum...

Tom

[chester]

Hey mate, i had a lot of trouble with mine overheating mainly on hills.What i did to mine was:
Drain and flush and refill with new coolant.
Replaced the thermostat.
Replaced the fan.
But the main thing that helped was i had my radiator triple flowed,best money i spent.
Triple flow means they pull the tanks off and put baffles in to deflect the water so it flows across the radiator 3 times instead of once.

[aaron]

My mate's 4.2 was over heating turnd out to be the clutch fan id cheak that ?

[vespasprint150]

Hi there,
went to mechanic, fixed/changed the fan (wasn't running smoothly), flushed and changed the coolant (took an expensive one), checked the thermostat and it is working fine and, the temp. is till hot, even after only 20min of runnin in traffic). Further, when the engine is well hot (from half to three quarter of the gauge) the engine seems to knock, kind of missing a stroke at low rev (1, 1.5) from time to time. High revs no problems (at high rev the temp. goes down quickly). Acceleration is (slow) as usual, consumption maybe bit high?

HEEELP, I don't have a backup car...

Tom

[GUtsy ute]

Hi there,
went to mechanic, fixed/changed the fan (wasn't running smoothly), flushed and changed the coolant (took an expensive one), checked the thermostat and it is working fine and, the temp. is till hot, even after only 20min of runnin in traffic). Further, when the engine is well hot (from half to three quarter of the gauge) the engine seems to knock, kind of missing a stroke at low rev (1, 1.5) from time to time. High revs no problems (at high rev the temp. goes down quickly). Acceleration is (slow) as usual, consumption maybe bit high?

HEEELP, I don't have a backup car...

Tom

Hi Tom,

Sounds like your cooling system is OK if it cools quickly at high revs and everything has been checked. Do you have a full shroud on your radiator that encloses the fan?
Without a shroud the fan sucks air from the sides and not as much through the radiator especially at slow speed.
This means it is circulating the hot air under the bonnet more and not sucking as much fresh air in from the front.
Another thing you can do is put spacers between the bonnet and the hinges to let the hot air escape faster if you don't
mind the look of the bonnet jacked up at the back.
I have seen vented bonnets as well to draw air in and also let hot air escape.
About the economy, how strong is the spark from the coil?
On my 4.2 I fitted a new coil and extended the tip of the rotor button as the gap between the tip and the pins
in the distributor cap is too big resulting in a weak spark at the plugs.
The best thing to do would be go to breakerless ignition, it's not that expensive and makes a big difference
in economy and performance.
I have seen places that sell the extended rotor buttons, will try to find them again.
Also a good set of plug leads if you don't have them already.
Gee it's easy to spend other peoples money!!!

Cheers Gavin

[NoBody]

My first suggestion would be to check your radiator, especially seen the circumstances you're constantly driving in. Is your radiator still clean and letting through enough air?

Although a lot has already been checked and/or changed by the mechanics and, perhaps, yourself, I didn't read anything here yet about your radiator's state :)

[Silver]

distributor timing very retarded, or choke stuck partly on?

[vespasprint150]

Thanks guys,

what's about the head gasket? Apparently is slight worn and would need to be changed. High consumption and hot engine are signs of worn gasket? (oil is not that dirty and engine not burning oil).

Radiator is clean and the fan is a proper one. 'll check the distributor over the week-end.

[NoBody]

Head gasket seems unlikely to me, unless it's burning coolant and/or there's oil in your cooling system and/or there's coolant in your oilsystem.. Head gasket's main task is, by my knowledge, to prevent leaking between outlet gas, coolant and oil.

I gave it some thought again and my next guess would be your waterpump or dynamo. There's a chance that, with heating up, some friction arises between one of them pulleys and the device driven by it. Also bad bearings could cause one of those devices to run very heavily. That would certainly explain the overheating (the engine has to constantly work harder) as well as it's high fuel usage. It would also cause faster wearing of the belts driving them.

[MQ MAD]

Thanks guys,

what's about the head gasket? Apparently is slight worn and would need to be changed. High consumption and hot engine are signs of worn gasket? (oil is not that dirty and engine not burning oil).

Radiator is clean and the fan is a proper one. 'll check the distributor over the week-end.

Dont touch the timing if its running fine
The fan it self could be correct , but the fan clutch hub itself could be stuffed and not doin its job
Id get the fan clutch hub checked, maybe replaced
Then or either get the radiator rodded out (entails a proper clean by a specialist ,not by a hose)
Your radiator cooling tubes could be blocked (common issue) or the cooling fins themselves could be cactus, entailing anew radiator

Most of the GQ and onwards radiators are a very thin alloy core radiator and are suseptable to blockage
IMHO i doubt the massive high mileage has to do with a cooling issue
A massive cooling issue usually results in a cracked head/head gasket issue and breaking down on the roadside, not high fuel consumption

[andrew373]

Replace the thermostat with a lower temp rating
Replace radiator with a hevy duty radiator 2inch thick(50mm)triple core copper/brass or a
3inch thick aussie desert cooler quad core

[vespasprint150]

Hi there,

"winter" is coming up even here in bangladesh: replaced the fan clutch hub and replaced the radiator tube (the big black one) and the car seems now to be running better. Let's see whats happens when the hot seasons will come back.

[vespasprint150]

Hi,
The 4.2 carby 1994 is still overheating... Work done so far:

- new water pump,
- gauge check
- head gasket changed
- cluch fan checked

Next steps? Get rid of the radiator thermostat? Cry?

Tom

[NissanGQ4.2]

Ha you done what MQ MAD Had suggested and had the radiator rodded out (entails a proper clean by a specialist ,not by a hose)?

That's what I would do first.

I have problems with mine running hot on hot days when stop starting and that is due 2 one of the bottom cores been damaged and was blocked by the radiator specialist .

Cheers

Todd

[cliff]

Do not get rid of the thermostat. This will cause more problems than fix, it is needed to cool the engine effectively because it by-passes through the small outlet at the top of the housing until the engine reaches operating temp. I have fitted an aftermarket alloy radiator and twin oil coolers, no probs with overheating now.

[vespasprint150]

Done, done, done.

Temp goes down as soon as I switch off the air-con.

Looked at new radiator available here in Bangladesh and they all look the same as the one it is in right now (and it is 4 years old only).

Could someone suggest a heavy duity radiator that I could ship in? Who sells (and can ship internationally) aftermarket radiators, triple or quad core?

Alternatively, would a more performing fan & blades do?

Few pictures of the radiator, fan blade and air/con condenser.

[97_gq_lwb]

Have you checked that the thermo fans are actually blowing the air through the radiator.