Will tightening the head bold on E300TD 1997 fix a mystery light coolant loss? - PeachParts Mercedes-Benz Forum

Olivier · #1 11-15-2009, 05:08 AM

Something strange happen with the coolant. I had the low coolant warning light coming up 2 month ago, I top it up. A week later, same story. I top it up and drive like this for a few days, got to MB, get 3 bottles of the proper coolant and replaced as much as I could emptying most of it.
Drive a week with no bother, but yesterday I checked and I saw the coolant in the reservoir was a bit lower then it should be, about 25Cl.
I have looked everywhere for a leak. Nothing.
The indie did a sniff test in the reservoir. Nothing.
The latest tells me there is not supposetly any head gasket problem as there is no fuel in the coolant, I am running mainly on oil tho, that might be why the sniff test came out negative

But I canot see any leak anywaere? This is an odd one for me.
Anyone had the same bother?
Should I try to thighten the head a wee bit more like I just read in a post, 45 degres?
Cheers.
Olivier

TMAllison · #2 11-15-2009, 10:30 AM

I might start pulling inj's and examining their tips and heat sheilds, and then send a sample of the oil off for analysis and see if it comes back with glycol first.

Olivier · #3 11-15-2009, 10:47 AM

I changed the injectors last year, would they still be damaged?
Could you explain a bit more what am I suppose to look for with glycol? Oh, what oil are you taling about? The engine oil?
What would the heat shield do to the coolant?
cheers.
Olivier

Just did a wee search, you think the coolant is going into the engine oil, is it it? My oil is the same level, no mayo on the cap, all normal, this is why I am puzzled

BenzDiesel · #4 11-15-2009, 11:30 AM

Fix head gasket or worse fix cracked head. Wishful thinking only prolongs the agony.

BenzDiesel

Diesel911 · #5 11-15-2009, 11:33 AM

The only information I have to look at is a 1995 606 Engine. On that Engine after several torque steps the Head Bolts are tightend more by turning the heads 90 Degrees.

This means that they cannot be re-tightend they way they are because there is no final Torque to retighten it to.

The only way to do it would be to loosen all, and starte from the begining as if you had removed the Cylinder Head.
And, this would bring up the issue of the Head Gasket already being compressed.

I did not read the manual in detail and did not notice of your are supposed to replace the Head Bolts everytime you remove them or not.

TMAllison I believe was saying to pull some Injectors and Heat shields to that you look at them and see if there is an unusual color/residue on them that might indicate a small amount of coolant is getting into the combustin chamber an exiting you tail pipe as steam.

Having the Engine Oil analyzed would tell you if you were haveing a Coolant (glycol?) Leak inside of the Engine somewhere. (This assumes that you have not changed your Oil lately.)
As opposed to some tiny pin hole external leak that you cannot see because it evaporates too fast.
Also sometimes Coolant Leaks do not leak unless the Engine is warmed up.

Olivier · #6 11-15-2009, 11:49 AM

Cheers BenzDiesel, I close my eyes and I don't look at it, I don't see it, it will go away, nope?
Just been cheeky.

Diesel 911 apparently the bolts need to be changed as they are streching bolts. I think they are 22 of them, I got the exact number somewhere as I asked MB for a quote on what is needed to do the HG, the parts alones are 200 pounds...

I looked at the engine hot and cold, nothing. There are some white smoke on hard acceleration, but this could be due to my fuel. I rev the car high on stationnary for awhile and there was the white smoke, but the exhaust is bone dry, with some steam I would expect a bit of moisture/ condensation, no?

If there was some coolant going into the engine, the oil level should raise, no?

I might go with the "teeny" leak somwhere that cannot be seen as I am not going to do the HG not knowing for sure if this it it or not.

Thank you.

Olivier

Actually, soon I'll run the car on dino, gosh, I should have thought of this before

( a brain could be dangerous they say...), this will tell me if the white smoke is the fuel or steam from the coolant.

tankowner · #7 11-15-2009, 01:09 PM

Quote:

Originally Posted by Olivier

Actually, soon I'll run the car on dino, gosh, I should have thought of this before

( a brain could be dangerous they say...), this will tell me if the white smoke is the fuel or steam from the coolant.

Yeah, you need to get it running diesel first. Run a couple tanks of diesel through and see how things progress with your white smoke. The white smoke is not a good indicator, but you won't know if it is moisture in you oil or not unless you run some diesel for a while.

Change your own oil too, and examine it as it comes out. Perhaps get some clear platic containers so that you can see what it looks like after you drain it. If it looks more brown than black or frothy like a milkshake, well then you have some problems. Of course it could be a small amount and you may not be able to see it very well, so then I would follow Terry's advice and send a sample off to get it tested. I have never done it, but I think it costs about $30 and at least that way you would know.

Matt L · #8 11-15-2009, 01:18 PM

Quote:

Originally Posted by Diesel911

I did not read the manual in detail and did not notice of your are supposed to replace the Head Bolts everytime you remove them or not.

There are length specifications for the bolts. If they are too long, they must be replaced, but otherwise they may be reused.

patbob · #9 11-15-2009, 02:08 PM

Unless you've just put the head back on, tighening the bolts further probably won't solve your coolant leak. Those bolts are on there really tight, if they loosened up on their own, you've got a lot more problems than just loose head bolts.

Like others have said, you need to find out where the coolant is going first. An oil test might indicate some is leaking into the oil. Checking for excessive pressure or combustion products in the cooling system would be a good idea too. Also check for an ordinary dripping leak too.

sasquatchgeoff · #10 11-15-2009, 02:41 PM

Better yet, just pull the head and replace the head gasket and be done with it. I don't know your situation, but I ran into a similar circumstance and ended up rebuilding the top end. My car is now a daily driver and very important to my business. If you have eventual plans to get rid of the car, then head gasket R&R may not be the most prudent solution. Whatever the case, there is lots of advice on this forum to head in the right direction.

Diesel911 · #11 11-15-2009, 03:14 PM

Quote:

Originally Posted by Matt L

There are length specifications for the bolts. If they are too long, they must be replaced, but otherwise they may be reused.

Thanks for the info.

hey_allen · #12 11-17-2009, 01:17 PM

Is there any possibility that it's something as simple as the coolant pump dribbling it out the shaft weep hole?

I just got done replacing the coolant pump on my SEC, and it didn't show much sign until it'd gotten to the point where it was dumping half a gallon a week. Up to that time, you couldn't really see any traces other than an occasional white crusty mark from the coolant drying on one of the hoses.

It wasn't going into the oil (no slime in the pan or on the dipstick), and it wasn't burning it (no sickeningly sweet exhaust smell), so I kept an eye on it until I finally spotted where it was going. Once I had an idea what was going on, I was able to actually catch it leaking, but only when the engine was running. Once it was shut off, maybe 2-3 more drips, and nothing else.

Olivier · #13 11-17-2009, 03:54 PM

Hi HA,
Where is the shaft weep hole, what is it made for?
I was told about it previously and looked at the pump but nada? Nothing.
Its odd.
Should I open the pump and chage a seal?
Cheers.
Olivier

engatwork · #14 11-17-2009, 07:31 PM

Look closely at the passenger side rear of the block. If it is leaking externally then that is where you will see it leaking. You will need a flashlight. Oh yea, you can run em like that as long as you keep the coolant level where it is supposed to be.

Olivier · #15 11-18-2009, 01:43 PM

Cheers.
Was the the dealer today and the mechanic show me properly where from the pump it should leak, if its the pump, there is the shaft but also a pipe going from the pump shaft to the ground, there might be a leak there, anyhow, its a new pump needed if its there.
Not the right weather to go under the car now, I wait unti its going to be a wee dryer...