(Home) Thermostat & head gasket

My partner's brother owns a 2.2 Townace turbo diesel (2CT engine) and broke down this morning. He said that there was a bang, a puff of smoke from the exhaust, and steam pouring out the passenger side. He said the system seemed to be empty of water.

We drove up to meet him with a few gallons of water to refill it (about 35 miles away). He told me that when he checked under the passenger seat, the water bottle for the radiator had the lid off it, so he thinks it was it that blew off with the pressure which caused the bang.

He filled it up and got the engine going again, although it was hard to start. I followed him for about 8 miles before steam poured out again. We stopped again and he refilled. We got another 8 miles or so and there was a puff of smoke from the exhaust and he had to stop (we'd just joined the motorway).

This time, the return hose to the radiator had blown off, but I managed to get it on again (very fiddly) and he refilled it and eventually got it running again. We got to my house where we had a look at the engine and wondered what the problem could have been.

He said there had been no indication of any problem. The temperature gauge was sitting at cold though, when the first bang happened.

I was wondering if the thermostat was maybe jammed closed and the water wasn't reaching the radiator to get cooled ? I've no idea where the temperature probe is, but if it was on the 'other' side of the jam, I guess it would sit at cold ?

He's hoping that his head gasket isn't blown, or any cracks in the head, but I think he'll be very lucky if he gets away with just replacing the thermostat.

So, does anyone think my analysis is right or am I barking up the wrong tree ? We spent ages trying to find where the thermostat is, but gave up in the end. I spent a few hours searching the internet and came across this site which seems excellent.

There seemed to be conflicting views on the location of the thermostat though. In one area, I saw people talk about it being behind the alternator, under the air conditioning. In another area, it was at the other end of the return hose of the radiator, on the passenger side of the engine.

Looking at some of the WEB links, a Russian site had some schematics in a download area (which I think is really superb) and one of them shows it at the end of the return hose that goes into the bottom of the radiator. Would this be correct ?

Also, it looks like it could be very difficult to get at the 2 nuts/bolts - is there a simple way of doing this or do we need to take lots of other parts off first to get at it ?

We reckon that he should be able to drive it if we take the thermostat out, as long as he keeps under 50mph (as I read elsewhere on this site). At least the coolant (well, water, until he gets it sorted out) should be able to flow through the system and get cooled.

We're hoping to try getting the old thermostat out tomorrow, so I don't know how often people read this board and if I'll have a reply by then.

He lives in Belfast, so I'm not sure what the availability of parts is like. I guess Toyota dealers are pretty likely to have thermostats in stock though, especially as I've read that the same 2CT engine appears to be used in the Camry.

I'd appreciate any comments. Oh, and sorry about the long story. BTW, I drive a 2.0 Corolla Diesel myself, so this has got me thinking about potential problems with it, as it is 9 years old.

Thanks in advance,

Terry - near Belfast

- (#3899) Terry Moffitt, 20 Jul 02

from what i can see in toyota engine manual, thermostat appears to be at bottom, but pic is a bit vague.
the question i would ask is where is all this pressure coming from to blow pipes off etc. even if thermostat is stuck,water should just circulate until it gets v. hot! then it should lift rad cap and allow water into expansion tank?

- (#3900) eddie arrowsmith, 20 Jul 02

the thermostat is in the short housing that the return rad pipe connects to, and yes it is a pain to get to.
should be some hints/tips on townace.com. the stat is fitted to a range of engines and a local spares shop should have one in stock.
where is the pressure coming from, is the puff of smoke steam?
hth

- (#3901) Clive, 21 Jul 02

Terry. I think that someone has to "bite the bullet" here and completely strip the cooling system for inspection & renovation. For the system to pressurize to such an extent that a hose "blows off", indicates that there is a serious blockage somewhere, coupled with a pressure build up, brought about, either by static water boiling, or, cylinder pressure transfer into the waterways from a failing head gasket. The latter can be checked by running the engine with the rad/filler cap removed (temporarily) and checking to see if there is any excessive turbulence in the water, at the filler neck, at light throttle openings. A complete flush through of the radiator (or both rads if it is 4WD) will be a start, also, a check on the operation of the viscous fan (if fitted), the water pump and the integrity of the radiator/filler cap and, most important, the operation of the expansion tank hoses which allow transfer of "expanded" water into this tank, and it's essential return to the main system on cooling.
The thermostat is located on the left hand side of the engine, under the injection pump and, yes, it is a bit fiddly to get at but not too bad. Also, your mention of running without the thermostat will be a good start and will remove a potential restriction while the system is checked. Unusually, the thermostat is on the return side of the cooling system so follow the radiator to block return hose, and you will find the thermostat situated at the block end of the hose. Two 8mm bolts (I think) and an "O" ring seal.
My own view is that, because regular checks of the various levels, ie, oil, water etc, are a bit of a nuisance involving seat moving, lifting etc, even the most conscientous owners tend to be a bit lax, and lowering water levels do go unnoticed, especially if there is a fault with any of the many warning lights/indicators. Also, with coolant inhibitors rarely used in Japan, and these vehicles being around 10 years old, my view is that there is an unacceptable amount of sludge & debris, in the cooling system, which, sometimes, the importers and successive owners, ignore. Have a good read, on the Ace Answers site, regarding the "Achillees Heel" of these vehicles, ie, the cooling system.

- (#3905) John Davis, 21 Jul 02

Terry, sounds like head gasket (or maybe rad, cap is you're very lucky.) I'm in Newtownards. Hursts are good for import parts, if you need a rad cap get it from them for the specific model. 'Stats are universal, though. Caps are known to fail, opening at too low a pressure. Fill system, start engine with cap off. Water forcing out= HG or head. If you need a head, Beatties in Camlough are good, but one for a 3C might be difficult... Email direct if you want.
Oh, stat is on pass. side, behind aircon pump, in the return hose spigot.

David

- (#3907) david miller, 21 Jul 02

Many thanks everyone for getting back so quickly. We're just about to start in to the job now. We'll try out everything you've suggessted and see what happens and I'll report back.

Thanks again,

Terry

- (#3909) Terry Moffitt, 21 Jul 02

Well, we eventually got the old thermostat out. The rubber seal/O ring looks like it has a small crack in part of it so it'll need replaced. We put it all back together without the thermostat - it took many tries to stop the O ring falling out - we ended up putting a drop of vaseline on it and it worked fine.

Filled the radiator, started her up, and water was squirting out the overflow pipe of the expansion tank. As he revved it, I noticed some water squirting from the radiator cap. So, maybe it was the cap all along ?

It seems to be burning black smoke - no sign of white. It's harder to start than it used to be though. So, it looks like he'll have to get a new radiator cap (a proper Toyota one), a thermostat, and an O ring, yeah ?

Oh, and his temperature gauge still doesn't seem to be working. Any idea where on the engine the sensor might be, in case the wire has fallen off ? Looking at the diagrams online, I think it shows something near the top of the front of the engine ?

I checked the fuse, but it's fine. Well, that's as far as we can go today. One thing we tried was starting it with the radiator cap off - bad idea, water flew up like a volcano and sprayed us :-)

I'm guessing this is the water pump forcing it up ?

Terry

- (#3911) Terry Moffitt, 21 Jul 02

"I'm guessing this is the water pump forcing it up "
I hope that you are right Terry but, a water pump will not neccessarily pressurise the system as, after all, it is not a "positive" displacement pump but just an impeller. High pressure and "water like a volcano", with the rad cap off does not look good but, I'll keep my fingers crossed for you. If the pressure was high enough to lift the rad cap, it is unlikely that the pump could raise that kind of pressure.
The temperature gauge "sender" is quite near the coolant filler (radiator) cap, at the front of the engine and can be seen with only the passenger seat up.

- (#3912) John Davis, 21 Jul 02

Sounds like the head gasket has gone, OK, or possibly the head itself. Head itself is more likely with the hard starting symptom (BTDT) Cracks develop between the valves over time, not a problem until one penetrates the water jacket.Even then, don't expect to be steaming out the exhaust, cylinder pressures are higher than coolant, so gas goes out, not water in.

Shouldn't force water out straight after starting. Even a faulty rad cap will hold SOME pressure until the engine warms.
Temp gauge sender is under the inlet manifold, roughly under no.3. The sensors John refers to are for the aircon.

Sorry to be negative, but I've been there twice in three years... You need to look for an underlying reason- duff viscous fan or something. Problem is that the gauge, even when working, tends to indicate overheating only after the water has left the system already

David
- (#3913) david miller, 21 Jul 02

Thanks David, yes, I gave some duff gen there. The two sensors, near the filler cap, are for aircon and, as David rightly points out, the temperature sender is on the side of the block, under the inlet manifold.
Yes, I agree with David re the temperature gauge. It seems to be "all or nothing" and I am currently trying to work out the fitting of some sort of back up sensor (or early warning sensor, possibly sonic) so that the driver does not have to rely on that lazy and indifferent device on the dashboard.

- (#3914) John Davis, 21 Jul 02

I'm afraid that the prognosis is not good here, the waterpump on a car is only a basic impeller pump, it creates no pressure and only circulates the coolant around the system, the pressure is created by the water heating up & trying to expand, this is retained by the rad cap, as 0.9bar the cap spring gives up trying to retain this pressure & opens, allowing the excess coolant into the expansion tank (if the cap works correctly this coolant is then sucked back into the system by the slight vacuum created as the water cools & contracts) the whole reason for having a pressurised system is so that the water can be above 100 degrees C, the most effecient temperature for an engine to run, without it being pressurised the water would boil away at 100C. As I said earlier the pressure is created by the water being hot, so if it pressurising whilst cold, there is only one place the pressure can be coming from is from the cylinder compression, therefore either cracked block, cylinder to water jacket. or else it's the 2CT & 3CT's achilles heel & the head gasket has gone, 'fraid to say it's almost certainly HG. p.s. your first post says 2.2l 2CT, if it's 2CT then it's 2 litre, if its 2.2 litre then its 3CT, largely irrelevant, but could be crucial when ordering parts. regards Rob.

- (#3916) Rob Drinkwater, 21 Jul 02

It sounds like it's bad news for my partner's brother in that case. I have to admit that when the water shot up on starting, I thought it seemed like a bit too much pressure for just a water pump and thought to myself "Oh no, it's a crack in the head and the high compression in the engine is causing this", but I didn't want to worry him in case I was wrong. The water was cold, so it definitely wasn't steam that was causing the pressure.

Another thing that worried me was the water being force out the overflow of the expansion tank. Sometimes it was water spluttering, but when he revved it, it looked a little like steam. I carefully put my hand in front and although it was quite hot, it wasn't scalding. At that point, I thought of exhaust fumes from the cylinder.

I used to own a Corolla GT Twin Cam which blew the head gasket (and cracked the head), water mixed with the oil and the big end went (in a BIG way). Some similar symptoms though. Myself and 3 friends just replaced the engine (£500 recon) and only took about 4 hours. Working on the Townace seems to be really awkward and takes a lot longer.

Anyway, he's going to get a new thermostat (which he may not actually have needed), O ring, and radiator cap (again, which he may not actually need if it's pressure from a damaged head/head gasket). As you say, there must be some other underlying problem, which I agree is probably either the head gasket or a cracked head. Either way, it's going to cost him quite a lot to fix. And he thought the thermostat sounded expensive at around £17 (from what I read elsewhere) !

Thanks for all the help guys. I'll let you know whatever he decides to do. In the meantime he's without transport and has a wife and 4 kids, so he'll have to bus it to work.

Terry

- (#3926) Terry Moffitt, 21 Jul 02

Well, my partner's brother (Paul) got a radiator cap, thermostat and O-ring and fitted them. The Toyota dealer said it sounded like a head gasket gone and gave him a phone number of a local repair shop. It turns out that the owner of the repair shop knows my partner's brother's father and uncles.

The head isn't cracked, but is slightly warped and needs skimmed. There doesn't appear to be any white goo from water mixing with oil, thankfully. He's going to replace the timing belt/chain (not sure which it is) at the same timing as doing the gasket (makes sense). He also says there's a small leak in the radiator under the drivers seat that he can solder. Cost will be around £300-£400 and should be complete in a few days.

The repair shop owner/engineer owns a Townace and Liteace himself, so I guess he knows a fair bit about them.

I'll post again with whatever the final outcome is, along with what Paul thought of the repair, treatment, etc.

Terry

- (#3943) Terry Moffitt, 23 Jul 02