some general cooling system questions - PeachParts Mercedes-Benz Forum

xp190 · #1 02-26-2004, 02:21 PM

Hi Guys

A neighbour of mine gave me his old car for free since it broke down on him.

I started looking over the car, originally the problem was with the shifter cable, I replaced that and now I can shift and start in all the correct gears.

A new issues has come up on top of that, and I am a bit intrigued with it.

The car spews water from the exhaust and the exhaust smells terribly, as if it is burning collant, I'm not sure because I never smelled burnt coolant before. There is also a lot of white smoke, more evidence towards coolant burning. So it looks like one of the head gaskets, since it's a V6 might be blown and is leaking quite a BIG amount of coolant into to the cylinders. That's fine, I will replace both head gaskets once I have the opportunity.

There is another problem on top of this though. I started the car and let it spew water for a while, then I shut it down and I started checking the coolant hoses. I know there is supposed to be pressure in some of them, but not when the engine is off.

The car has no heating, which suggest to me that the thermostat is stuck open. There is pressure in one of the mian hoses going to the radiator and under the radiator cup which is confusing me.

I think the radiator might be clogged, the thermostat stuck open, and this adds to the leaking head gasket. Right now I am waiting to see if the pressure will drop as the car cools down, or if it won't.

If anyone is interested, the car is a 1991 Plymouth Acclaim, a major POS, but it was free, and still might run for a while if I fix up what I can on my own.

xp

jas2wa · #2 02-26-2004, 02:37 PM

Hmm, that must be the Mitsu 3.0L v6, right?

Sounds like the heater core (or route to it) may be blocked if it has no heat. You'd still get pressure in the radiator hoses and under the rad cap.

If the cooling system is tight (no leaks) and functioning properly, it SHOULD maintain pressure even when the car is off. Well, at least M-Benz's do (based on my experiences of late trying to remedy a coolant leak in my 84 300TD).

xp190 · #3 02-26-2004, 03:14 PM

yup, it is the V6 3.0L, very good engine, just a bad car that they put it into.

As for the pressure I thought it was only supposed to be there when the pump is going. I can check this since I now have two of these cars, just the one that works my dad took to work.

xp

manny · #4 02-26-2004, 04:17 PM

It all has to do with your blown headgasket.
Ran into that with my 3.3 l Chrysler too.
You likely have some compression leaking into the cooling system.
Whatever you do, DO NOT even loosen the radcap, when the coolant is still hot.

xp190 · #5 02-27-2004, 09:38 AM

Thanx Manny for the input

One I strip this sucker down and replace the head gasket I guess I'll know for sure, but it's good to know about the rad cap, it had me worried

maybe the radiator is still good, just the thermostat needs to go.

xp

Ferdman · #6 02-27-2004, 10:11 AM

XP, I recommend not running the engine again until you replace the head gaskets. You're liable to bend/break a connecting rod or two if the engine attempts to compress a combustion chamber mostly full of coolant. Then you'll have a junker for sure.

pmckechnie · #7 02-27-2004, 10:54 AM

It is real common for these engins to blow head gaskets at around 100K miles. I also recommend you don't even start the engine again until you fix the problem. While the heads are off, have the valve guide seals replaced. This is another common problem on these engines. You will have the timing belt off so might as well replace it. This is more work, but you might as well fix it also. I would also replace the water pump unless you know it has been replaced. Actually, that goes for the belt also. The timming belt runs the water pump. I have had several of these engines in Caravans, all with over 200K miles, and all ran great.

xp190 · #8 02-28-2004, 10:51 AM

Hi guys, thanx so much for the input

Right now the car is in my garage, I started stripping it so there is no chance of it even starting right now

So far its going quite well, I'm about to get at the timing belt and I do plan on replacing it along with the water pump, tensioner, and all the seals that come into play. I didn't know about the valve guide seals, I'll check my hanes manual for the procedure.

The engine has 210,000km on it and its a 91 model, my dad has the same thing except that his is a 94 model, it looks like I will have to do the same thing on his car after I'm done with this one. Fortunately I don't have to rely on this car yet, it was a gift, but it's good to have in case I need to do some work on one of my other cars, sort of a back up.

I find it very interesting that the engine is made by mitsubishi, and as difficult as it is to get at some parts, it's quite easy to work with, but this is before I get down to the sprockets and pulleys and crankshaft bolt which I'm sure will give me lots of problems

xp

xp190 · #9 02-28-2004, 10:38 PM

Hi guys

Does anyone have any tested ways on how to get the crankshaft bolt off on this engine? the mitsubishi v6 3.0L?

I tried locking the fly wheel, but anything I stuck in there broke in half, then I tried using a few bolts to attach to the vibration dampner and using a crowbar to lock it, but the bolts break off or bend, yet the crankshaft bolt won't budge... wish I had an air gun to do this...

xp