High Temperature...again!!


This is my first posting so bear with me...
My question relates to a problem that seems to have been covered quite extensively, but none of the answers seem to cover my problem exactly.
I have just bought a 1992 fourtrak 2.8TDX. It looks immaculate and has a full main dealer service history up to 106K, and has been serviced privately since then, (now 119K).
I drove it home along both motorway and country lanes for about 100 miles. Along the lanes there was no problem with the temperature. On the motorway up to about 65mph, again no problem. Over that, (max 80mph) the temperature gauge rose quickly towards overheating, although never quite reaching it because I reduced speed back to 60mph which saw it almost immeadiately lower to normal levels, ( about halfway on the gauge).
The problem was particularly bad when climbing hills at above 65mph.
Any ideas?
many thanks

Over Heating

Hi. I have the same problem,at the same sort of speeds, same sort of driving conditions, and a well maintained truck. '91, 2.8TDX' . I have back flushed the rad and block, changed the thermostat, with some improvement. Still have to resort to using the heater to bring the temp under control during long hi speed motorway climbs. (solo,no trailer) Will run up to 90MPH indicated, and hold but sends temp through the roof, even with heater blower on max.

(Just for the times when you just have to get out of the hassle with the heavies and the sunday,once in a while 'shall we use the motorway dear', types in the middle lane) And I am of the age when I should know better.)

There a number of post,s mentioning the failure of the viscous fan coupling,and work rounds,this will be my next little job after I sort out the rear lights/trailer and accessory plug wiring. Who designed the wiring harness for these brilliant workhorses,he wants his sushi shoving where the sun do'es not shine.

May your Diffs sing sweetly.

Edward (ews) '92 Fourtrak 2.8 TDX

High Temp under load

Come one guys, lets have some comments one this issue. Here's two of us with the same problem, similar trucks, Their must be others with similar/same problems. Lets have some thoughts on the matter. Do we both have a knackered viscous fan drive. No comments on the sushi required.

Edward (ews) '92 Fourtrak 2.8 TDX

Further to last post

Just gone through all service history of my truck. I have found a bill for a replacement rad. (prior to my purchase) This was from a breakers yard, is it possible the rad is of a different spec, ie from a non turbo/intercooled truck. this rad is not fitted with a exspansion bottle,which i have seen on other 2.8 TDX's, and do'es not have the fittings on the side to where it attaches. Any thoughts.

Edward (ews) '92 Fourtrak 2.8 TDX


Hi, for a start Fourtrak Independent,s all have an expansion water bottle fitted as standard "to allow water to expand into the bottle when it gets hot vacuum then draws the water back into the rad If this bottle is missing water is venting out & your loosing it when it gets hot.Second-hand rads are a stupid policy at the best of times "not your fault someone else trying to penny pinch" the veins clog up with silt & block result very bad cooling result "OVERHEATING" without looking at the rad in question who knows what its off.Try first removing the rad wash it out carefully with a low pressure hosepipe (not full blast this will damage the rad veins) you will find the bottom portion is full of silt & other crap.Backflush the whole system inc the engine block to remove silt ect remove the thermostat & check it put hosepipe in there as well to aid backflushing.Refit the rad buy an expansion water bottle & use it otherwise your wasting your time because it will continue to overheat My radiator cost £85.00p to recondition as the "Main Dealers" wanted about 300 quid plus VAT for a new one if your problem persists try a recon rad YELLOW PAGES regards Paul

Hi Ive had the same problem w

Hi Ive had the same problem with my 1991 fourtrak, it turned out to be the rad full of mud and crap! It took me about an hour to take the rad out wash the fins out with a hose pipe. Hope this helps

Do you have spotlights fited?

Do you have spotlights fited? Daihatsu did a study some years back now that showed how spots fitted in front of the grill can couse cooling problems at high speed. Not becouse of the direct blockage of air going into the grill, but becouse at higher speeds a vortex develops behind the spots. This basicly stops the air from moving throught the rad, as it just spines around it self behind the spots.

Any veiws expresed in this thread by me are purely from my own experience, and (sometimes) falible memory. Hope my comments help, but please don't take them as gospel.

Over Heating

Hi. Thanks for all your replies.

So far I have hosed through the rad to remove external crud, mud/dead flies and what have you,regulary use the commpresor to blow through as well, have no spots in front of the grill, but have small rectangular ones on the bumper. I have used a brand of rad / block cleaner as per the instructions, then removed the hose's and back flushed the rad, packing rags around the hose to get max flow through the rad, very little crud came out, was disapointed not to see lots of crap flush out. did the same with the block after removing the thermostat, again very litte crud, renewed the thermostat, (82 Degrees if I remember correct).

Bear in mind that I have no expansion bottle,and I understand what has been said about the water loss. If filled to the brim ,she will blow the coolant out. Expansion as she heats up, on checking when she is cold the coolant level will be halfway between the top of the rad and the core, it will stay at this level, I never have to top her up,even when I have abused the girl and really heated her up, and I have given her some abuse up the old Porlock Hill road, not the caravaners toll route, just to see if what I had done had some effect, temp was was far slower to rise,noticeble improvement, but sustained hi speed driving is still controled by watching the temp gauge. Problem is still there, exactly as the original poster described it.

Many thanks to you all.( She's a girl,definitly. And she's called Chunky)

Edward (ews) '92 Fourtrak 2.8 TDX

High Temp, again

Hi All.

Thanks for all your replys.
And she's a leaf sprung puddle jumper, not a coil sprung rocking chair. !!!!
Decided to to try the broom stick test, as recomended,for testing the viscous fan conection. well the fan made a damd good try at be'ing a circular saw, no problems there.The fan tried to chew up the handle from barely warm to hot. At cold,pre staring slight resistance to hand turning, warm still the same, hot noticable resistance to turning.
Any suggestions, any one. One thing I have not changed ,the temp sender unit. Any thoughts!!!!!!!!!! This is niggling me, and getting right up my nose,had this problem since just after buying this great little truck, and no reflection on the couple who owned it before me, they just used to poodle around with her, and looked after her,and never pushed her to any extreme's.

Edward (ews) '92 Fourtrak 2.8 TDX