450 sel crank but no start

[zeppelinboy]

Let me know if you have any thoughts on this.

79 450 sel (4.5)

My wife ran into a snowbank at low speed and ruptured the radiator. She didn't realize this and kept driving for about 5 miles and then the car died and refused to start again. Just had the car towed to my house tonight.

The engine cranks over freely, but will not start. So, the engine did not overheat and sieze. I have not checked anything yet, except to see that the radiator is indeed toast. Tomorrow (when it warms up to the anazing hi of 20° F) I will check all the usual, spark, fuel, etc.

Any thoughts on what could be going on here? I know, not alot of info yet, but I just wanted to get the ball rolling.

Also, does anybody know which w116 radiators will interchange with the 4.5 model? I will be heading to the salvage yard since I can't seem to find any sources for a new one.

Thanks!

[oscar]

I hope Pat's wrong too.  Got a bit of a shock to see how bad things may be in this situation, but I'll tell a similar story to what happened in a F250.  On our way during a trip this 5.8L motor got sluggish and died quickly.  Trying to restart the engine wouldn't turn and no way would it kick over.  A little while later it would turn very slowly.  Of course it overheated but not sure why exactly, no leaks, nor was it being raced.

Back at the workshops the engine turned normally once the engine had cooled but they couldn't ge it started.  Now this happened about three years ago and I can't remember being told what the fault was except they managed to get it going again after it had cooled down again.  Hopefully in your case the pistons got hot and expanded but I assume your attempts at turning it over was done after the engine had cooled.

When you say "cranks over freely", do you mean without much resistance as though spark plugs were removed or do you mean cranked over normally as though nothing was wrong but without ignition as if the coil was unplugged? I'm going to be hopelessly optimistic and say your spark plugs are melted, but I fear worse.

[zeppelinboy]

Hey guys, thanks for the replies.

To clear things up, I am not positive if the car actually overheated or not, my wife never looked at the temp gauge (it is her first car). Liquid coolant was still coming out of the radiator when the car died on her.

When I said cranks over freely, I meant that it cranks normally but  no ignition. I was implying that the engine was not siezed.

Now for todays update.

The a/c condensor and radiator are damaged beyond repair. The radiator was pushed back into the fan and recieved a severe lashing, also the bottom tank was mangled. The fan lost a blade fom the contact with the radiator.

I checked compression and the results were favorable 120 +/- 5 PSI on all cylinders.

I put new spark plugs in and attempted to fire her up. To my suprise, she grumbled to life, but ran very poorly. I only ran her for about 30 seconds because of not having a radiator attached. When I got out, I realized that I had also disconnected the tranny cooler lines and had baptized my snow covered driveway with a nice coating of ATF.

Right now, I am thinking that the radiator soaked everything and probably shorted something in the ignition (distributor, coil?) causing the no start. Tomorrow, I shall pull all electrical items apart and clean and dry everything, hopefully this will cure the problems.

Thanks again for your thoughts. If anything else comes to mind, please let me know.

Also, if anyone knows if other w116 radiators can be used for the 4.5 please advise.

[s class]

I would think the 450SEL uses the same radiator as the 350SE, but I'm not sure.  In any case, 350's are scarce in the U.S.

Ryan

[john skene]

If Styria is correct and the rings are locked into the piston grooves by carbon you don't have a lot to lose by trying something radical (but only as a last resort).

See if a spray of ether will fire it up initially. If that works you need to free up the rings to get some compression to keep it running. Buy some Slick 50 or similar activated Teflon modified oil that should act to free up the rings, put a little in each cylinder and spin the engine over without the spark plugs so that the bores and rings are covered, plus any excess is blown out. Put the plugs back in and see if it will start (the oil may give you enough compression)

If it starts and keeps going, pour the rest of the activated Teflon oil into the engine and keep it going at about 2000 revs for about 40 minutes, it should gradually smooth out and run freer by then, so take it for a run, putting a load on the engine by regular small time increments of full throttle to load up the rings.

If it doesn't start see if the ether trick works again.  You may have to try this a lot of times to keep it running, but the idea is to keep it running until the Teflon starts to coat the rings and start them working. But as I said, try this only when you have nothing to lose.

[Papalangi]

I' pull the distributor cap and spray it with WD40 then wipe it out with a somewhat lint free cloth.

It doesn't take much condensation to kill the ignition.

Michael

[zeppelinboy]

Thanks again to everyone for your replies.

Here's an update.

I was able to salvage the radiator for temporary service until I can locate a suitable replacement by cutting out the damaged tubes (6 of them) and soldering them shut.


It seems that the Benz gods were smiling upon this 450.
After liberally hosing down the innards of the distributor with water repellent and carb cleaner and then blasting with compressed air and buttoning everything up, she cranked right up and runs better than before, thanks to the new plugs.

It is very surprising how susceptible this distribulor is to water. As an experiment, I misted the distributor with a sparay battle and the engine died immediately, not to crank again until I repeated the above drying procedure.

Also, I noticed something rather peculiar during my inspection of the ignition system. The plug that connects to the 4 point round port of the ignition "black box" (switching unit) is totally missing. There is a coil and the two series resistors, but no connection to the large 4 prong port on the box. I need to study the wiring tomorrow to determine what the previous owner did with the wiring.

Does anyone know if there is a common modification that would eliminate the need for this connection?


Thanks!!

[Papalangi]

It is very surprising how susceptible this distribulor is to water. As an experiment, I misted the distributor with a sparay battle and the engine died immediately, not to crank again until I repeated the above drying procedure.

I once steam cleaned the engine on my '87 5.0 Mustang.  I got about 6 miles down the road before it slowed to a crawl.  As I got out to check it out, I noticed a lot of heat coming out from underneath.  Sure enough I could see the cats glowing in the dark, I'd guess around 1000-1100F.  "Not good" I say to myself.  I let it cool down, wiped the damp distributor cap dry, fired it and headed home.

Michael

[Papalangi]

Well, I would give Papalangi full marks for pin pointing the problem. Still don't understand how the innards of the distributor could have been affected by the damage caused by the snowbank.  Regarding your ignition set-up, I find PB's assessment intriguing. Regards, Styria

It was the voice of experience.  I had a pin hole in the upper tank of my '74 Ford F250 and it shut down at a stop light.

Michael