Announcement

**europa88** · 19 August 2008, 11:19

I would have It checked by a reputable mechanic. it seems to have happened a few times,you may only have a leak from the rad but It would be worth getting a pressure test and maybe a sniffer test!

**Tallyman** · 19 August 2008, 11:27

How much coolant did you need to put in to top it back up to the brim of the radiator? If it was vast amounts then you've either got a leak (hose split or perished somewhere), your rad cap needs replacing or you may have pin holes in the radiator itself. Can you see any signs of water leaking anywhere? If you've got the standard red coollant in there then it usually will leave a stain around the point it leaks from.

Other possibilities are airlocks (did you "burp" the system when you filled it the last time, including having the heater pipes set to hot), water pump failing, thermostat failing, radiator fan not working (presuming the 3rd gen has the usual viscous fan fitted). When you tightened the aircon belt did you check the tightness of the other belts as well?

Also, if you are towing then this puts additional strain on the cooling system. I replaced my radiator this year before towing down to Cornwall and even on the flat the temp guage (an auxhilliary one) showed at least a 4C increase in temp over normal and up to another 15C when pulling up a long hill. If you have an automatic then the increase in temp of the ATF fluid will make the coolant going back into the engine much hotter. If so, try fitting an extra ATF oil cooler into the circuit to take some of the strain off the bottom of the radiator.

**TonyN** · 19 August 2008, 16:46

If you're losing water with no signs of a leak, its probably the head gasket or head.

Trucks that get hot under load, but don't lose water are the ones with clogged rads.

Change your cap and stat, just to be sure, then get a garage to test the cooling system pressure, or the sniffer test for exhaust gas in the coolant, if it fails any of these the head has to come off and be checked.

**dc.washington** · 20 August 2008, 15:42

ok chaps thanks for the advice, heres where i am

when it overheated it took 4/5 litres to fill the rad back up

no visable leaks anywhwere

water pump is working

haven't checked thermastat - mmm not sure how to do that

i've bought some rad cleaner, shall i run that through anyway? then get a mechanic to do take a look? or get it to a mechanic asap. anyone recomend a surf specialistic essex/london area ?

**Tallyman** · 20 August 2008, 15:54

That's a lot of water to lose in a short time, unless it's been losing water for weeks, although I can't see it running OK with more than a litre sort in the rad. Did you notice any steam coming from under the bonnet before it went? If not, it could be a leak on the lines/hoses to the rear heater, so you wouldn't see that as they are under the middle of the truck.

Do as TonyN suggests. Also, have you or anyone else been offroading it? If so, did you hose out the cooling fins of the rad as a mud blocked core can cause this sort of problem.

Edit: As regards the thermostat, you would need to remove it and check the opening temperature in a pan of near boiling water. It would probably be just as quick then to replace it anyway. Do you notice the truck either taking a long time for the coolant to heat up (thermostat stuck open) or heating up quickly and getting hotter as you drive only a couple of miles (stuck closed but less likely)? Probably not easy if you only have the standard in-dash temp guage as they seem to show the exact same temperature anywhere from 40C to 120C, and only above that do they seem to climb quickly to "Fried Engine" red line.

**dc.washington** · 21 August 2008, 09:20

when she over heated the overflow thingy next to the rad popped off with lots of steam coming out.

i checked the oil again last night, no sign of water in there. i got rained off before i put my rad cleaner in. the great british summer

when i last over heated i popped the bonnet and the fan wasnt going round and like i said before the air con wasnt working. not to sure if the belt drives some part of the air con. anyway there was a bit of play i the belt i tighten that, filled the rad back up and fired the engine up and let it run on the drive way for like 40 mins. temp gauge just moved up to halfway and stayed there. Now since then ive just driven short trips around town and temp gauge has just been normal, no signs of leaks. it all seemed back to normal.

until towing last week, 2 hours towing, i glanced at the temp gauge all seem normal until i noticed the engine check light come on.

We're past my knowledge as a mechanic, i dont seem to have white smoke coming from the exhaust and no water in the oil do you think my head is safe and my next port of call is the stat ?

there is a toyota main dealer near to me maybe i should give them a call, although ive heard toyota uk arent to keen on touching import

again thanks for all your help

**Tallyman** · 22 August 2008, 23:27

It would be worth getting the coolant pressure checked for gas in the water, which would confirm if the heads gone or not. Alternatively it could be the head gasket, but if you are sure that there is no water in the oil then it's more likely that it's either an airlock (burp the system) or possibly a faulty rad cap.

As it happens when towing it could be the ATF fluid getting very hot. As mentioned previously think about an ATF oil cooler.

Your fan, presuming it's the viscous type driven off the water pump pulley, should be turning when the engine is going. If it's an electric after-market one then usually these only cut in when activated by the engine temp sensor. So if it's mechanical and not working then it's either broken or totally devoid of oil and will need stripping and rebuilding. There's a thread on here somewhere with a detailed description of how to strip and repair it.

EDIT: Just seen it below on another thread. Here's the link: http://www.hiluxsurf.co.uk/forums/sh...1&postcount=10

**dc.washington** · 26 August 2008, 12:28

thanks for the all the advice very much appreicated.

at the weekend i added the rad flush and then topped up. could you tell me how i burp the system please?

i did about 20 miles in her yesterday, temp gauge stayed in the middle, when i got home popped the bonnet the fan was running although i could feel a lot of hot air being blown off. I'll monitor how much water in the rad up unto the week and try and gauge if shes losing more.

i think ill take it to a mechaninc and get it the once over.

**yorta2** · 28 August 2008, 03:54

The big thing with the fan is the viscous clutch. Next time you have the engine up to normal temperature, stop the car, open the bonnet, and get yourself into a position where you can see the fan rotating. Then, switch off the ignition key and watch the fan blades. If the fan stops within about 5 or 6 blades passing your eyes, then it is okay. If it rotates for more than that, then the viscous coupling needs to be pulled out and repaired. Good luck.

**dc.washington** · 3 September 2008, 15:14

ok chaps, just thought i'd update you given all the help everyones given me.

i flushed my rad, checked my fan (its stops in 5!)

refilled her and have been monitoring the temp every since, saturday morning i checked the oil for water - not a trace!

i towed a speedboat for an hour. kept my speed constant didnt put the engine under to much stress.

checked my fluid when i stopped and had cooled down, still full !?

a mystery??!

ive got a new thermostat and some of the toyota coolant from roughtrax's. i guess ill add those and just monitor her.. i dont really know if theres anything i can do other than that.

**yorta2** · 5 September 2008, 06:15

It seems you are a very lucky boy, Mr dc.washington, and you have learned much.

Announcement

overheating - another question

overheating - another question

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment