Low coolant

ChileanKJ · **Posted:** Sun Dec 07, 2008 12:04 pm

a few weeks ago my jeep started to show the low coolant light, so I checked and refilled for the fist time in a year (last refill was when i changed the thermostat), then I went fishing two weeks ago, and I was driving on the beach in 4HI with 4 adults and 3 kids on the jeep suddenly the ding ding warned about something. stoped take a look and the temp was hi, everybody out, change to 4LO and drive a little to get the temp back to normal, this take 1 or 2 minutes, the low coolant start to light again, refilled, and now two week later low coolant light again, I didn't find any coolant drip, any ideas about where the coolant is going?

thanks

BlackLibertyCRD · **Posted:** Sun Dec 07, 2008 12:33 pm

Possible blew head gasket when it overheated since it loosing every two weeks. Maybe some bars leak or lower pressure cap can tie you over for a little while.

ChileanKJ · **Posted:** Sun Dec 07, 2008 12:36 pm

But before the overheat I had the leak too.

BlackLibertyCRD · **Posted:** Sun Dec 07, 2008 12:55 pm

I looked at the past and current event. In the past it took a year to get low, currently it takes only two week to get low. The past is no problem, current there is a problem with the more rapid lost of coolant. It has to be leaking internally or externally.

ChileanKJ · **Posted:** Sun Dec 07, 2008 3:57 pm

I'm changing the oil to check the presence of water, I'll let you know what came out. In the manual I see that when temp rice it will make 5 ding and you have to stop, keep the engine runing to lower the temp, so the dings may be a life saver before any trouble. Hope!!

ChileanKJ · **Posted:** Sun Dec 07, 2008 6:16 pm

No water on the oil... Its a relief, what else could be happening with the coolant?

BlackLibertyCRD · **Posted:** Sun Dec 07, 2008 6:26 pm

If it's a head gasket it could be going out the exhaust. The water pump can drip behind the timing cover.
Best to really check if you have a leak at all. Pressure test the system to about 15 lbs and look for leaks. If the gauge on the pressure tester leaks down then you have a leak.

Jeepjeepster · **Posted:** Sun Dec 07, 2008 6:45 pm

Check the radiator.

warp2diesel · **Posted:** Sun Dec 07, 2008 8:46 pm

Shops use pressure testers to find coolant leaks, bad or loose hose clamp is cheaper than engine replacement. If you had a leaky head gasket your coolant would smell bad and the pressure would shoot up fast even at no load idle.

WolverineFW · **Posted:** Sun Dec 07, 2008 11:16 pm

Blown head gasket can leak into the cylinders and vaporize and go out the exhaust. If it is a big leak your exhaust may be white at idle.

I had a Civic with the same problem. No water in the oil, but it was leaking into the cylinders.

nursecosmo · **Posted:** Mon Dec 08, 2008 1:13 am

If it were leaking that much coolant past the head gasket into a cylinder, you would almost certainly smell it in the exhaust, especially at startup.

Uffe · **Posted:** Mon Dec 08, 2008 3:14 am

WolverineFW wrote:

Blown head gasket can leak into the cylinders and vaporize and go out the exhaust. If it is a big leak your exhaust may be white at idle.

I had a Civic with the same problem. No water in the oil, but it was leaking into the cylinders.

No way that low-pressure water can enter a chamber pressurized to 100bars. You're not fooling physics with regard to pressure and flow direction.

What you will get is air in the water and that will blow the water out the cap of the radiator.

IF you happen to get water in, you'll be getting it into the oil somewhere with low pressure. But why would a low pressure area crack a headgasket? Seems odd to me.

Uffe · **Posted:** Mon Dec 08, 2008 3:32 am

ChileanKJ wrote:

No water on the oil... Its a relief, what else could be happening with the coolant?

I would check those POS hose clamps at the bottom of the radiator. My 03 clamps failed the day I bought the KJ second-hand. I had a fluid change that day, luckily my girl discovered the leak and told me of it.

I am pretty sure you don't have a head gasket problem, this thing is related more to cooling hoses and clamps I'd say. Never heard of a CRD KJ blow a gasket before.

warp2diesel · **Posted:** Mon Dec 08, 2008 8:31 am

Uffe wrote:

WolverineFW wrote:

Blown head gasket can leak into the cylinders and vaporize and go out the exhaust. If it is a big leak your exhaust may be white at idle.

I had a Civic with the same problem. No water in the oil, but it was leaking into the cylinders.

No way that low-pressure water can enter a chamber pressurized to 100bars. You're not fooling physics with regard to pressure and flow direction.

What you will get is air in the water and that will blow the water out the cap of the radiator.

IF you happen to get water in, you'll be getting it into the oil somewhere with low pressure. But why would a low pressure area crack a headgasket? Seems odd to me.

Our CRDs run at 0 pressure to positive pressure. Gassers even the turbo ones, run at a vacuum most of the time due to the throttle plate restriction.

retmil46 · **Posted:** Mon Dec 08, 2008 11:22 am

On the OM602 and 603 MB diesel engines, a common fault if overheated is either a cracked head or blown head gasket. There's some simple checks to do to see if either is the case -

Any evidence of oil or oil film in the coolant tank, or the coolant itself taking on a black color.

Starting up with the tank cap removed, if exhaust gases are bubbling up into the coolant tank.

Starting up the engine stone cold, check the radiator hoses. If they become pressurized and hard almost immediately, you have a head/head gasket leak into the cooling system.

You've already ruled out the other option - checking for water in the oil sump.

ChileanKJ · **Posted:** Mon Dec 08, 2008 11:34 am

I will check for pressure on the cooling system today, I don't have any extrange smell on the coolant, just the bad smell from the mopar coolant, I will check the exaust. I have a compressor but I don't have the tools to keep a constant 15psi pressure so I will have to take it to a service station to make it check tomorrow,

thanks for the responses, i'll let you know any find.

BlackLibertyCRD · **Posted:** Mon Dec 08, 2008 11:50 am

The pressure tester is a hand pump that goes on where the radiator cap comes off. You should be able to get one at a auto parts store.

Uffe · **Posted:** Mon Dec 08, 2008 1:01 pm

warp2diesel wrote:

Our CRDs run at 0 pressure to positive pressure. Gassers even the turbo ones, run at a vacuum most of the time due to the throttle plate restriction.

I hope you're not talking about cylinder pressure, 17.5:1 does create SOME pressure. About 100 bars. That air will go into the cooling system easily if there is a leak.

Obviously it depends on where the leak is in the engine, I assume there would be places where there is zero pressure, but my point was regarding the cylinder pressure - which is a lot more than zero.

UFO · **Posted:** Mon Dec 08, 2008 3:05 pm

^^^ Manifold pressure, on the off chance of a manifold gasket leak...

warp2diesel · **Posted:** Mon Dec 08, 2008 6:10 pm

Uffe wrote:

warp2diesel wrote:

Our CRDs run at 0 pressure to positive pressure. Gassers even the turbo ones, run at a vacuum most of the time due to the throttle plate restriction.

I hope you're not talking about cylinder pressure, 17.5:1 does create SOME pressure. About 100 bars. That air will go into the cooling system easily if there is a leak.

Obviously it depends on where the leak is in the engine, I assume there would be places where there is zero pressure, but my point was regarding the cylinder pressure - which is a lot more than zero.

Cylinder pressure at intake with no boost is 0. Gasser at idle runs at a vacuum so it sucks coolant into the cylinder. Some coolant will go into the cylinder of a turbo diesel under no boost conditions if there is pressure in the cooling system. Since the coolant is heavier than air it will fall on top of the piston and what will be forced into the cooling system will be a little air and a lot more exhaust. When the fuel burns the coolant turns into steam and Etheline glycol sludge that can stay in the cylinder if it does not burn up.
If the cylinder head were on the bottom and crankcase on top the coolant would be forced back into the cooling system along with a little air and a lot more exhaust. i can not recommend driving a Liberty CRD upside down to check it out.

Low coolant

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