does anybody know if hydrocarbons in the cool'nt is a definite sign that the headgasket or even worse the head are naff, my 2lt TD liteace 91 model is great allday long around town but as soon as i hit the motorway after 20 minutes the temp goes up,then down,then up and so on when I stop it is boiling was hoping it was a blocked rad so here i am crossed fingers and anything else i can cross.
regards keith
ps if any of the usual are reading IE clive (bristol),dave bright,chris turner,david miller,ian dunse and of course dave (sussex)editor thank you for making owning an ace such a joy,this site could;nt operate without you

- (#10274) keith wright, 20 Apr 04 12:48

HC in the fuel is normall a good sign that the seal between cylinder & coolant jacket has failed, where else would the HCs come from. In the Townie's case this means headgasket. What you describe, I'm afraid, is farly typical of headgasket/cracked head problems on the 'aces, run forever at tickover & above, hit the motorway & cruise & she boils over.

Sorry to be the bad tidings bearer, but from the evidence you have given it looks like yours has suffered with this vehicles only achilles heel.

HTH Rob.

- (#10274) Rob Drinkwater, 20 Apr 04 13:25

Hello Keith
Can you hear the viscose fan roar like a V8 engine every so often when travelling at speed? If not, replace it! Have you got a decent airflow through the front under the nosecone or is the number plate blocking it? Air ducting only occurs in the central portion of the intake (just where we mount our big plates.. Ray

- (#10274) Ray Ambler, 20 Apr 04 13:26

Your very welcome Keith.
Hydrocarbons in the coolant is usually associated with petrol engines. A sure sign of a cracked head or gasket on a diesel, is that the coolant will start to darken and eventually turn black. The combustion gasses contain soot from unburnt fuel and this causes the colour change.
Your problem could be a blocked radiator or perhaps a failing viscous coupling. If the temperature starts to increase over 3,000 revs then try slowing down a bit so that the revs are about 2,500. If the temperature starts to reduce, speed up again and see if it increases. If it does then its most likely to be the coupling. You could try a new radiator cap as they are prone to failing seals. This will result in a reduction in pressure that will allow the coolant to boil.

- (#10274) dave Bright (Bournemouth), 20 Apr 04 13:32

Antifreeze is a hydrocarbon. I'd of thought testing for CO2 would be a more reliable method of detecting combustion gasses in the coolant. Diesel HC emissions are in ppm orders whereas CO2 is in %'s. In bad cases wouldn't the contents of the expansion tank look like a washing machine? Difficult to see when driving tho!

- (#10274) Mark Harriott, 20 Apr 04 14:36

Keith,
When I first tried to drain my rad I used the drain point plastic key, after a struggle it came out with a very slow trickle of water. Gave up on that and whipped the bottom hose off - gush! Ran some rad clear stuff through a couple of times, and on the final drain tried the key again, this time straight up my arm and still more gunge came out! Try a good flush and flush again. Also check your auto box fluid as this could be adding to the over heating.
Other than that I think it's been covered above.
Thank you for the vote of thanks.

- (#10274) Clive (Bristol), 21 Apr 04 00:48

Picking up a couple of general points from Ray's posting ... I have never noticed this "V8 roar". Most of my driving is short trips around town or motorway cruising but I rarely cruise above 3,200rpm and don't think I hurry up hills. I do however have a "normal" front number plate mounted right on the front of the bumper, not obstructing the intake slots.
So not hearing the fan roar MAY not be sufficient reason for replacing the coupling.
Keith, what exactly do you mean by, "when I stop it is boiling"? I endorse what Clive says. If the unmodified Toyota temperature gauge is going "up" at all then something is wrong. My favourite is air locks, so drain, flush and refill SLOWLY - trickle it in, stop to let gurgling finish every time you hear it. Even then you need to check it's brim full under the cap every time it's cooled right down and it will need several top-ups.

- (#10274) Dave (Sussex), 21 Apr 04 04:38

a big thankyou to all of you. At least now i have some hope.
dave what i mean by boiling is that when i stop and look in the engine there is steam coming from the small hose coming from the lid of the expansion bottle not a huge amount just a trickle .
it seems that by increasing the revs brings the temp gauge down but it is the original gauge which seems to be useless anyway,will have to convert to the one i have read about on this site.
will try flushing and refilling slowly thankyou all once again will keep you posted ,hopefully once its done will be able to join you all on one of the ace jams.ps clive i grew up in bristol next time im in kingswood seeing my sister will try to look you up if you dont mind,cwmbran is only 25 min over the bridge.

- (#10274) keith wright, 21 Apr 04 06:01

Normal operation is that a cupful or two (?) of coolant goes into the expansion bottle every time the engine heats up, then should all get sucked back when it cools. It is very hot when it leaves the system, even above 100 degC since the system should be pressurised. This means it will "boil" as it comes out even though inside the system is not boiling. However the route it takes should be to first go down a pipe and mix with whatever is already in the expansion tank. If "steam" is coming out of the overflow of the expansion tank then three possibilites spring to mind:
there is not enough cool fluid in the expansion tank to start with, to condense this steam,
far too much is leaving the system (air pocket locked in system?) and all the contents of the expansion tank are at nerly 100degC,
or there is something wrong with the pipework at the top of the expansion tank.
You need to see how full is the expansion tank cold and hot (clean it out - shake some gravel round inside it, and hold a torch against the top) and how hot does the side of the tank feel (care) when this steam is coming out.

- (#10274) Dave (Sussex), 21 Apr 04 06:21

thankyou dave.
when i stop the expansion tank is empty dont know where the water goes.
where is the best place to empty the coolent,the bottom hose or is there a drain plug ?
by the way the last time it boiled up i noticed that the rad was cold even though the engine was hot so i hope this means that it is a blockage or air lock
regards keith.

- (#10274) keith wright, 22 Apr 04 02:04

With 4WD auto you would have an extra horizontal radiator under the front. The drain tap on this is easy to reach under the front. I find this drains most of the system. There is a tap at the bottom of the normal radiator but hard to find/reach - from underneath with your fingertips, maybe easier if you haven't got the 4WD gear in the way. If your system is clogged you may need to take the bottom hose off. If not I find I can tip a cup of coolant in the top and see it promptly come out the front drain.
By the way - have you eliminated a thermostat stuck shut?

- (#10274) Dave (Sussex), 22 Apr 04 06:23

just ordered new thermostat and float type rad cap.
is the thermostat in the bottom hose?
i am also going to have the rad tested for a blockage
will keep you all posted
regards keith

- (#10274) keith wright, 23 Apr 04 04:37

Yes it is Keith. Just behind the waterpump, under the inlet manifold towards the front of the engine. Its 2 10mm bolts at 9 and 3 Oclock. Did you get a Toyota thermostat and a thermostat Oring?

- (#10274) dave Bright (Bournemouth), 23 Apr 04 04:55

dave thankyou for your reply.
found and changed stat(cant even see the housing took out expansion tank and still very awkward took me 3 hours,silly me had a leak on housing and snapped one of the bolts)anyway sorted it in the end,bad news though checked original stat and it is opening.didnt get a toyota stat but did get a toyota float type cap coming tuesday,noticed my cap has perished in several places.stat does look different but the same diameter.
WILL KEEP HOPING LOVE IT TO MUCH TO GIVE UP
regards keith

- (#10274) keith wright, 23 Apr 04 15:23

The main diference is the bit that opens. Toyota is 30 mm others are 25mm. If its 25mm then it will cause overheating due to the restricted flow.

- (#10274) dave Bright (Bournemouth), 23 Apr 04 15:37