Heater / Water Problem

[tavvi]

Hi,

back in April on a fairly long journey I noticed that the heater was not working very well - it only got lukewarm even when turned up. I also noticed that the temp guage had drifted close to the red. I took care for the remainder of the journey (a good 60 miles) and the guage went up and down but never into the red. Once the engine cooled I found that the expansion tank was empty and I needed to put about three litres into the rad. Since then the temp has been rock steady just below the mid point. However, I have had the heater off all that time - until last night. Again it was only lukewarm and didn't get any hotter until I'd turned it up to full at which point it was blowing as hot as I would have expected - but again I noticed the temp had climbed up toward the red. I've just checked and found that the expansion tank is empty and the rad needs water as well.

Any advice on what is likely to need fixed?

Regards.

[Bogus]

You might have airlocks ??

[tavvi]

You might have airlocks ??

Hi, thanks for the reply. I didn't burb the system when I topped it up in April.

I've just topped up the rad - again it needed about three litres. I left the cap off and idled the engine for a good twenty minutes with the back and front heaters turned up full. The water level dropped at the very start but only by about a cupful, after that it stayed full. The front and back heaters both threw out heat once the engine had heated up (the guage barely got off the bottom but I'm assuming that was because the rad cap was off). I did notice that the flow from the four front heater vents got progressively weaker from very strong from the leftmost passenger side to very weak on the rightmost driver side.

I suppose the next test will be to turn the heaters up full once the engine has got to normal temperature during my next journey (but I think I'll leave that until I am about a mile fromn home just in case).

[tavvi]

if your losing 3 litres it sounds like you have a leak some where if you have put 3 ltrs in twice now? if im reading correctly. then it seems a major leak.

Yes and it seems to go in a very short space of time. I called the mechanic I normally use and his first thought was that maybe a pipe had come off - especially given the reduced airflow from one side to the other. But it seems strange that the heaters worked and no water was lost when the rad cap was off - but maybe it's something that only happens under high pressure. I have a short trip planned for later this evening so maybe I'll learn more then. If its just a loose or worn pipe I'll be reasonably happy.

[tavvi]

Just back from a short trip (about 10 miles) - heater was turned up full and it was throwing out plenty of heat and the temp guage stayed slap bang in the middle all the way.

Playing about with the heater controls when I got back (engine still running) I found that there was no appreciable heat or temperature change up to about 27C and from there up to 32C (one step before the 'Hot' setting) temperature changes were appreciable but slight. At the 'Hot' setting it jumped to very hot.

Also, when moving from 26.5C to 27C the air outflow from the vents suddenly dropped down quite dramatically. It sounded like the air was being re-directed elsewhere - if anything it sounded like the flow had been stepped up a notch but I've no idea where it was coming out but it certainly wasn't through the dashboard vents.

Maybe the temp rise last night coinciding with the first use of the heater in months was just that - purely coincidental. It maybe that there is a slow leak that has taken 5 months to show up on the temp guage. I'll check the water level tomorrow but if anyone has any suggestions as to what might be going on I'd be grateful to hear them.

Thanks.

[tavvi]

in my case im worried i might have a cracked head.

I've only ever seen the needle creep towards the red (never reach it) on those two occasions and the truck drives like a dream otherwise so I hope I am not being over-optimistic in thinking there has been no significant damage. What are the typical signs of a cracked head?

[tonupteabag]

When the head went on my 3rd gen it had a slight power loss ,quite a bit of blue/grey smoke on initial start, this cleared once it had some heat in the engine, empty expansion bottle, and when i refilled the radiator and drove the truck 22 miles, it pushed a lot of water back in the expansion bottle which when it had cooled down it hadn't pulled the water back into the main rad, and it never overheated anytime

[tavvi]

Checked rad level this morning - still full to top and a clear pink colour, which I assume is due to the red coolant.
No white smoke on startup (or any other colour for that matter).
No wet carpet on passenger side.
Basically no sign off any ill effects at all but I'm still worried at what appears to have been a sudden loss of about 3 litres!
I'll just keep checking every day this week and I have lined up the mechanic for start of next week. Even if he can't find anything I think the minimum required is a flush and refill replacing rad cap and stat - any other suggestions as to what should be included in a 'service' of the cooling system?

[Overland Tonka]

You have the rear heater connected...have you checked the pipes are not corroded and may have a small leak which is difficult to spot?

[tavvi]

You have the rear heater connected...have you checked the pipes are not corroded and may have a small leak which is difficult to spot?

Thanks for your interest.

On Sunday when I burped the system and had both heaters on this was the first time in 4 years I'd used the rear heater so I'm assuming the trigger for the coolant loss is not switching the rear heater on, although this is not to say that there isn't still a problem related to the rear heater.

Yesterday I had to top up the expansion tank by 275ml - the rad level was fine. Today no top up of either was necessary. On both days mileage was only about 10-12 miles. I've kept the heaters off since Sunday and intend keeping it this way until the start of next week when the mechanic will be available. I've a 200 mile trip at the weekend and want to minimise risk. I'm hopeful that coolant levels will be ok between now and next week if only to help through a process of elimination. If that is the case then hopefully I can rule out something as serious as a cracked head. The truck has never been used for towing, I rarely do over 60mph and I never hammer it from cold so I think I'd be extremely unlucky if there was a cracked head.

Hopefully some faffing about with the front heater controls next week will shed some light on this. TBH I'd rather get to the bottom of this and deal with the necessary expense than drive about in ignorance wondering when or if something serious was going to happen. On the other hand I also want to avoid speculative repairs - although the mechanic I use is usually more careful with my money than I am!

Cheers.

[tonupteabag]

Tavvi
I drive in a similar manner and still ended with the head cracked. I do not tow, i don't hammer the engine from cold, the truck has seen 90mph once AFTER the new head was fitted. I was doing a thorough shakedown of the engine as i was trying to push the engine (once it was upto temp) to see if it was going to show up any more problems before i relaxed knowing it was 100%. since then i have had no water loss or excess pressure...Well unless you count my credit card

[tavvi]

I drive in a similar manner and still ended with the head cracked. I do not tow, i don't hammer the engine from cold, the truck has seen 90mph once AFTER the new head was fitted. I was doing a thorough shakedown of the engine as i was trying to push the engine (once it was upto temp) to see if it was going to show up any more problems before i relaxed knowing it was 100%. since then i have had no water loss or excess pressure...Well unless you count my credit card

Can't blame me for being optimistic, but I'm probably tempting fate. I can't get away from the fact that the last time this happened was 5 months ago and since then I've driven the truck pretty much every day with some pretty long journeys including a 14 hour round trip between Edinburgh and Hereford the week after it first happened (pretty dull at 55-60mph all the way!) and in all that time there have been (and still aren't) any secondary symptoms such as white smoke on start-up.

The only sensible thing I can find to link the two events is use of the front heater - there has been no heater use at all in the intervening 5 months. I am struggling to think of anything else.

The one thing that I did notice was that the rear window de-mister stopped working at the start of the year - the light doesn't even come on when I press the button on the dash. I thought that might be a broken cable but haven't looked into this yet. I checked the fuses and they are all ok so I am thinking this is extremely unlikely to be related.

The only other niggle with the truck is something I posted on months ago. There is an intermittent whine / squeal coming from the underside which stops when I press the accelerator. I can go weeks without the noise and it tends to appear more in drier weather so I suspect it may be something needing greased. I have had this checked out by two different mechanics - one a transnmission specialist who is adamant it is not a transmission problem. Both said they had trouble hearing it and thought it was a cosmetic niggle that wasn't worth spending money on investigating - so again I am assuming this has zero to do with the current issue.

At the moment I am clutching at straws. The only other common factor linking the two events is that both happened while driving through West Lothian - unwise at any time

[tonupteabag]

No i understand the reluctance with the head cracked scenario, I started hearing a bit of gurgling a few months back but no water loss and very little pressure, so i ignored it thinking it would eventually show itself and it did by emptying the expansion bottle and top of the rad, i refilled them thinking "it's a one-off" anyhow the following day i only did 12miles and coolant was pushed from the rad to the expansion bottle and it didn't return add that to watching bubbling in the expansion bottle it pretty much gave it away,,,

[gary-r]

west lothian - mmmmmm that explains it

its the wee gremlins that live under lithgae bridge - they've sneaked under the bonnet when you weren't looking

[tavvi]

Still losing coolant at a very slow rate - approximately 25-50 mls per week depending on mileage. There are none of the secondary symptoms of a cracked head so I am still optimistic that it is something reasonably innocuous.

However, I've been topping up using the genuine Toyota red coolant which is quite expensive so I've finally decided to get this diagnosed (and sorted) once and for all. I'm getting the cooling system pressure tested next week and will take it from there.

Even if it eventually turns out to be a cracked head I will be getting that done rather than sell the truck. I phoned Stevo at the Stockport Engine Company today and apparently sourcing heads is no longer a problem for them. A fully built up head kit from them is £899 including VAT.