Coolant leak.

[Cuda]

I had to take my caravan down to Canberra last week for repairs, about 20 mins. from home I noticed the water temp. rising dramatically (i have a separate temp. gauge) and at the same time noticed steam coming out from under the bonnet. I pulled over and the top hose had come off the radiator, the hose clamp was on tight? reconnected clamp, limped into a town, topped up the water tank, continued to Canberra with no problems. However, since then I'm losing water from somewhere. It seems to vent water to just below min. every time I fill the tank like the system is over-pressurized. The hoses are all tight, there appear to be no leaks from around them there is coolant on top of the transfer case and on the sump bash plate (R/H side looking into the engine bay). I have changed the rad. cap (not that that should cause that problem) I can only come up with radiator trouble but appears to be all right. Any suggestions.
Thanks in advance.
Cuda.

 

[Old.Tony]

It's possible that the head has cracked, or the head gasket has started leaking. If the temperature rose over 120C there's a good chance the head has suffered and it's venting combustion gas into the coolant system, which will pressurise the overflow bottle. This will force liquid out of the overflow until it can just bubble away (you should be able to check that while the engine is running). The drain for this is on the vehicle right hand side and it might just be splashing of the drips landing on the transfer case. The transfer case has no physical connection to the engine coolant.

 

[Cuda]

It's possible that the head has cracked, or the head gasket has started leaking. If the temperature rose over 120C there's a good chance the head has suffered and it's venting combustion gas into the coolant system, which will pressurise the overflow bottle. This will force liquid out of the overflow until it can just bubble away (you should be able to check that while the engine is running). The drain for this is on the vehicle right hand side and it might just be splashing of the drips landing on the transfer case. The transfer case has no physical connection to the engine coolant.

Thanks, mate. Temp got up to 127C (could not pull over because of guard rails on side of the highway for about 600 meters). Getting it checked out on Wednesday. Would the gasket or head going explain why the hose came off at the start?

 

[Old.Tony]

Thanks, mate. Temp got up to 127C (could not pull over because of guard rails on side of the highway for about 600 meters). Getting it checked out on Wednesday. Would the gasket or head going explain why the hose came off at the start?

I would think it's more likely the other way around, the hose came off preventing coolant flow, the head overheated and, being alloy subjected to 750+ degrees and intense pressures underneath, it let go. It's possible that it's the other way around, of course - never say never until you know, but if your hose was off/split/broken, that's the more likely culprit.

 

[KevinE]

Just a thought, but maybe the hose coming off has let air into the system & that may be causing your overheating issues? If so, you just need to bleed the air out, or get someone to do it for you. You should know if the head or gasket has gone by the colour of the engine oil (it goes milky)

 

[Cuda]

Just a thought, but maybe the hose coming off has let air into the system & that may be causing your overheating issues? If so, you just need to bleed the air out, or get someone to do it for you. You should know if the head or gasket has gone by the colour of the engine oil (it goes milky)

Checked that

I would think it's more likely the other way around, the hose came off preventing coolant flow, the head overheated and, being alloy subjected to 750+ degrees and intense pressures underneath, it let go. It's possible that it's the other way around, of course - never say never until you know, but if your hose was off/split/broken, that's the more likely culprit.

If I have to take the head off, what else would you do? 2008 model with 164,000 k. I have always babied the bloody thing (oil change every 5,000k,-filter at 10, warm it up, letting it run a while before turning off, etc.)
, not milky and no white smoke coming from the exhaust.

 

[Cuda]

Just a thought, but maybe the hose coming off has let air into the system & that may be causing your overheating issues? If so, you just need to bleed the air out, or get someone to do it for you. You should know if the head or gasket has gone by the colour of the engine oil (it goes milky)

Kevin, I did check, oil is not milky, and no white smoke coming from the exhaust.

 

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if air is passing into water , when cold fill the radiator, with cap off have someone rev the engine and you will see air bubbles comming through the water .....thermostat stuck open or closed will cause overheating.. you can check thermo by heating it in a pot and using a kitchen probe (roast)thermostat to see if its working ok

 

[Old.Tony]

I wouldn't take off the head straight away, no sir. The coolant system can be checked for exhaust gas first, which would be a good indicator if there's a crack in the head or a leaking head gasket. It's considerably faster and cheaper than removing the head.

If that test does indicate exhaust gas in the coolant, then the head would probably be best removed. If you're removing the head, it would be prudent to have a look at the bore in a cylinder with the piston at its lower point as it ought to be indicative of the condition of the other cylinders. If you've treated your car well, it'll be just like mine - when the mechanic changed my cylinder head, he remarked that the engine looked like it had been recently rebuilt (untouched, just serviced and cared for, for 320,000km).

The other thing to consider while it's all off (because you have to removing the timing chain to remove the head) is a close examination of the timing chains, sprockets and tensioners. Because we didn't know the cause of our coolant leak, I had the mechanic replace the water pump (which turned out was still almost new inside, but I wasn't aware of this at the time).

 

[Nig]

Souds familiar, is a water pipe to the head drivers side front under the fuel rail near the temp sender, has a oring seal, this leaks the water will make its way around the engine to the opposite side and drop down, also check the turbo water intake this will leak coolant down the inside of a cove tube to the ground also blows back , both these will blow bock over the trannie.

 

[Cuda]

Update. Took the truck down to a local mechanical shop a couple of days ago. They ran tests including pressurizing the system, turn out the only issue was faulty hose clamps. The top hose must have been getting old and the clamps (The ones that run a screw through 2 cams, brackets -can't think of another way to describe them) weren't taking up the slack. Wanted to test the truck before this post. Drove down to Canberra (from Southern Highlands) picked up caravan drove back without any problems. Looks like I dodged an expensive bullet.