Still overheating

[MattF]

Ok nice one, one more though: Is there a write up on doing a full coolant flush?

Disconnect both radiator hoses and remove the thermostat. Shove the hosepipe into the lower radiator connection pipe on the block and flush through with tap water. Then shove the hosepipe into the thermostat housing and again flush through with tap water. Make sure the heater controls are set to maximum whilst doing so.

When you're refilling with coolant:

http://www.hiluxsurf.co.uk/forums/sh...0&postcount=12


There's Codlord's write-up here:

http://forums.bauchan.org/portal/hil...op/coolant.htm

[Bathafarn]

I am a bit shy as I'm a newbie and all, but like I said in an earlier post on this thread, I had the same symptoms as you - constant temperature under no load i.e just driving on the flat, but going uphill for more than the shortest period sent the needle towards the red... My mechanic - who works on loads of 4x4's in rural North Wales - flushed the rad for 30 mins and declared he had got all the crud out during a fluid change, then some while later I had the overheating problem you describe. I flushed through and got clear water but when the radiator was removed and put on its side huge gloops of gunk which had been lurking revealed themselves. I did not measure the volume but it mush have been a good 3/4 litre. I took the radiator to a specialist who told me that although the water was running from the top to the bottom and vis versa under flushing, the majority of the radiator waterways were blocked and the water had just taken the path of least resistance. New core and no overheating problems.
I think the only way to eliminate the radiator as a potential cause is to take it out and give it to a specialist, even if it does look OK.
I am only an amateur mechanic and there are loads of people on the site with centurys of experience, so I won't be upset if you don't follow my suggestion.

[Don Logan]

Disconnect both radiator hoses and remove the thermostat. Shove the hosepipe into the lower radiator connection pipe on the block and flush through with tap water. Then shove the hosepipe into the thermostat housing and again flush through with tap water. Make sure the heater controls are set to maximum whilst doing so.

When you're refilling with coolant:

http://www.hiluxsurf.co.uk/forums/sh...0&postcount=12


There's Codlord's write-up here:

http://forums.bauchan.org/portal/hil...op/coolant.htm

Sorry about this...

'Shove the hosepipe into the lower radiator connection pipe on the block':

Where's that? The big fat one at the bottom LHS of the rad or the big fat one at the top RHS of the rad?

'Shove the hosepipe into the thermostat housing':

The thermostat housing as in the vertical curved metal pipe with the bottom rad hose attached to it, or the thermostat housing as in the hole in the engine that you attach the said vertical metal pipe to?

I need this in complete noob terms if you wouldn't mind. Thanks a lot though, i'm getting there...

[gwh200]

To be honest mate, I would take the rad out and flush.

[Don Logan]

Hello mate, how's it going? Yeah, i'll do that but don't i still need to flush out the other 'non rad' parts of the cooling system as per Matt's post?

[MattF]

Hadn't noticed yours was the 3.0L. The thermostat is at the bottom, (return), on those.

Bottom = lower. Top = upper.

[Don Logan]

Right, so:

Drain rad.
Re-tighten drain plug.
Remove stat.
Replace vertical metal tube thing that covers stat (housing?).
Take both fat hoses (top RHS and bottom LHS) off of rad.
Turn engine on and set heaters to full.
Stick hosepipe into bottom fat hose.
Flush. (Isn't water just gonna pi$s back out of the gap between the hosepipe and the fat hose- Block with fist?)
Wait 10 mins.
Stop.
Stick hose into top fat hose.
Flush.
Wait 10 mins.
Stop.
Reconnect fat hoses.
Put stat back in.
Refill with 50/50 coolant/distilled water mix.
Run engine for 15-20 mins with (new) rad cap off, occasionally squeezing pipes.

Basically, stick water in through one fat hose and watch it exit through the other hose? Then reverse?

Thanks again.

[MattF]

Right, so:

Drain rad.
Re-tighten drain plug.
Remove stat.
Replace vertical metal tube thing that covers stat (housing?).
Take both fat hoses (top RHS and bottom LHS) off of rad.

Remove the rad if you want to flush it thoroughly, which is easier to do with the rad off the vehicle. As suggested by Don and Gra, best to flush the rad as thoroughly as humanly possible. Get it checked over if you have any doubt as to its internal condition.

Turn engine on and set heaters to full.

*Don't* run the engine at all until you've completely finished and refilled the system. Just set the heater controls to full. Nothing more.

Stick hosepipe into bottom fat hose.
Flush. (Isn't water just gonna pi$s back out of the gap between the hosepipe and the fat hose- Block with fist?)
Wait 10 mins.
Stop.
Stick hose into top fat hose.
Flush.
Wait 10 mins.
Stop.

Wrap a rag around the hose to stop the water flowing back out. There's no need for pauses between any process, btw.

Reconnect fat hoses.
Put stat back in.
Refill with 50/50 coolant/distilled water mix.

I'd pour some distilled water through the top hose to flush most of the tap water out, before you reconnect and refill.

Run engine for 15-20 mins with (new) rad cap off, occasionally squeezing pipes.

No. Do as mentioned in that post I linked to.

http://www.hiluxsurf.co.uk/forums/sh...0&postcount=12

The full thread:

http://www.hiluxsurf.co.uk/forums/sh...0&postcount=12

Basically, stick water in through one fat hose and watch it exit through the other hose? Then reverse?

That is pretty much the basic process, yes. When you take the 'stat out, you don't need to put the hose/metal pipe back on to flush the system, btw. Just poke the hosepipe directly into the housing where the 'stat goes. You're also best replacing the 'stat with a new one whilst you're flushing the system, rather than refitting the original.

[Don Logan]

Thanks for your help.

[davec170]

Hi! Some good advice given so far. You say rad' is looking ok/nearly new? Don't discount it's cores being blocked though. Here is a pic of a newish heater matrix that wasn't doing it's job of transfering heat:



Flushed it. All looks good, nice clean flow. Refitted it - still no heat transfer. Took end caps off, found it blocked with silicone sealer that had migrated from a previous owners bodged waterpump "repair"



New matrix (read Rad) was required.

Had very same symptoms as you (overheat under load) on my CX GTI T2. However, that was because my rad' looked like this:



Didn't leak coolant either!!

[Don Logan]

Took the rad out today and thoroughly flushed it. It was caked in a lot of mud in parts that you can't see when it's fitted... So i cleaned that and refitted it. No crap came out of it and it looks nearly new. Should i now flush the sysytem out with tap water or de-ionised water?

And just to clarify the best way of flushing: Should i remove the thermostat from the block and the top fat hose (return) from the rad and flush then backflush through these points? i.e: In through stat housing, out through top fat hose then reverse?

After flushing would it be an idea to stick in 5 litres of de-ionised water and run the engine for a bit to get rid of the tap water and then drain it back out before sticking 50/50 mix of red coolant and de-ionised water in?

And is it easy to remove the aircon rad to make cleaning the regular rad easier?

[Spoggle]

Had a similar problem on my 2.4 a couple of years ago. Ran fine on the flat but come to a hill, especially with the caravan on the back, and she got very hot and bothered. Had the head checked, ok, flushed the rad, loads of times, fitted atf cooler, and still she got hot. After a while noticed small leak on the top of the rad, so fitted new rad. Cured no problem since. Best money I've spent on the Surf.

Cheers Spoggle

[Albannach]

And just to clarify the best way of flushing: Should i remove the thermostat from the block and the top fat hose (return) from the rad and flush then backflush through these points? i.e: In through stat housing, out through top fat hose then reverse?

You already have that information.

[Don Logan]

Wow! Thanks Albannach!

I did all this stuff yesterday and took it for a run and it all seems fine! Now i just need to MOT, tax and insure it again. Chuffed with that, thanks for the all the advice.

Has anyone had any problems with MOT'ing after removing the rear ARB because of rear lift?

[stormforce]

it will come down to your mot tester.as there are fixing points on the truck for the arb and it was a factory fit then its meant to be there.As my tester has said due to the lift then its impossible to fit the arb on again so if its not there it can't be tested