1988 300e 6 cylinder gas..

103 engine I think....


i have reworked the head and i am ready to reinstall.... i have the bolt pattern and i know about cleaning the holes...

1. how do i tighten...? do i hand tighten then put the torq wrench on the number one bolt and tighten all the way or just snug down...

2. Do i tighten the bolts buy number all the way and then move on to the next?

3. after i hit the right torque numbers do i go an additional half turn?


4. what are the right torque numbers?

There are too many things you need to do when installing a head, that are not obvious, that if not done you may trash your heads or your engine.

I would recomend getting a service manual and follow step by step.

Search this site for "head" and read. There are many sad stories here.

It has been my experience to hand sung all the bolts then tighten in 3 stages 1st 55Nm 2nd turn all bolts in order 90 degrees, 3rd another 90 degrees, according to book.
You should also measure your bolts I would replace with new as they stretch and may break if you use the old ones.
good luck.

http://webwench.net/w123manuals/Service/W124/Index/103/01General.htm

Job 01-4050

stretch bults should NEVER be used more than one time.

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Those head bolts are tightened by torque then turn x degrees -- stretch bolts.

Given the cost of messing up, I would get new bolts, although there is nothing wrong with re-using them IF they are not too long.

For the procedure, you need to check a service manual (or the head gasket package, they often have instructions). As for the pattern, what you do it tighten each bolt, in the order illustrated, to the initial torque one bolt at a time. Some people like to do this in stages (that is, 25 ft/lbs then 35 ft/lbs, then the inital value, or something similar). You then start with the first bolt and turn the correct amount, usually 90 degrees in a single motion. Use a breaker bar, torque values aren't given. Repeat if there is a second (and maybe a third) stage.

Do clean and oil the bolts and holes, though -- dirty bolts will cause low actual torque at the head, and the gasket will blow.

The point of all this is that the bolts must be elastic enough to cope with the much greater expasion of aluminum than iron or steel -- the bolts are pre-loaded so that the head, when cold, will still be clamped down properly.

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!