Bad news- Need troubleshooting help for my 81 300D! - PeachParts Mercedes-Benz Forum

showme · #1 08-20-2013, 01:51 PM

I had a bad experience Friday evening coming back from a trip, and i need help determining what is wrong. I had been driving about an hour and a half, and suddenly I heard a pop and saw a puff of dark smoke in my rear view mirror. The popping (under the hood) conitnued about at about one second intervals, as I was driving about 70 on the interstate. I made it to the next off ramp about a quarter mile ahead, then turned into a parking lot and backed the car into a parking spot, ready for AAA. The car was still running, though the temp gauge was reading a little above normal. While making it to the parking lot, the engine was still occasionally puffing some smoke every 5 or ten seconds. It still started after I got it to the lot, and it will still start, (though it still "pops", almost like an exhaust donut gasket blew), now that I've had it towed home. I haven't pinpointed the location of the popping yet. Like an idiot, I decided to check the coolant level and got a scorched forearm to go with it as the cap jumped the pressure relief notch and blew off.

Dumb, I know. Something I've warned my kids about forever. Anyway, I'm coming to you all to see if anybody can give me a clue to what I'm dealing with, and how to start my repairs. I will say that along with the long drive, I was getting up to about 75 miles per hour for about 15 minutes before it happened. I was in rush hour traffic in St. Louis, and trying to "keep up" with traffic. Thanks for any and all comments. No need to tell me how stupid the radiator move was. I'm still kicking myself, and have the urgent care bill to remind me, along with a bandaged arm and now lots of pain. Thanks in advance for your help. Lee ps- I'm having to use the library's internet, so I'm only able to get on here for an hour each day, temporarily.

t walgamuth · #2 08-20-2013, 02:08 PM

Sorry it is happening to you.
1. Is the popping regular like a cylinder miss or random spacing?
2. How hot was the temp showing?

showme · #3 08-20-2013, 02:34 PM

Popping sounded more like a cylinder miss, I guess. Spacing was pretty well steady, not random. The temp was reading just above the 80c mark, which is normally usual for summer around here, though it may have been a touch higher. It wasn't redlining. That is, until I restarted it, and then it jumped up immediately but came back down immediately to 1/8th inch above the 80 mark. When it blew, it blew like it was hot, though. It sounds more like an exhaust pop than a metal clank, but it's definitely coming from under the hood somewhere. Oil and water were good when I left.

showme · #4 08-20-2013, 02:38 PM

I"ve got to get off of here due to time restrictions at this library. If anyone has any ideas, I can be texted at 314-605-6347. Otherwise it will be later on today before I can get back on again. Thanks for any suggestions or ideas, folks. I'm just hoping I didn't really screw something up. That would be my luck.

cooljjay · #5 08-20-2013, 03:27 PM

Sounds like an injector problem, I assume this is a non turbo? I wonder if one of the springs in an injector snapped....

rscurtis · #6 08-20-2013, 08:39 PM

Perhaps you have a combustion leak into the cooling system. I can remove the cap on my signature car at full temperature with nary a hiss. I am using a 7# cap, however. A leak into the cooling system would also account for your smoke and the occasional pop as the cap releases pressure.

Diesel911 · #7 08-20-2013, 08:53 PM

Quote:

Originally Posted by showme

I had a bad experience Friday evening coming back from a trip, and i need help determining what is wrong. I had been driving about an hour and a half, and suddenly I heard a pop and saw a puff of dark smoke in my rear view mirror. The popping (under the hood) conitnued about at about one second intervals, as I was driving about 70 on the interstate. I made it to the next off ramp about a quarter mile ahead, then turned into a parking lot and backed the car into a parking spot, ready for AAA. The car was still running, though the temp gauge was reading a little above normal. While making it to the parking lot, the engine was still occasionally puffing some smoke every 5 or ten seconds. It still started after I got it to the lot, and it will still start, (though it still "pops", almost like an exhaust donut gasket blew), now that I've had it towed home. I haven't pinpointed the location of the popping yet. Like an idiot, I decided to check the coolant level and got a scorched forearm to go with it as the cap jumped the pressure relief notch and blew off.

Dumb, I know. Something I've warned my kids about forever. Anyway, I'm coming to you all to see if anybody can give me a clue to what I'm dealing with, and how to start my repairs. I will say that along with the long drive, I was getting up to about 75 miles per hour for about 15 minutes before it happened. I was in rush hour traffic in St. Louis, and trying to "keep up" with traffic. Thanks for any and all comments. No need to tell me how stupid the radiator move was. I'm still kicking myself, and have the urgent care bill to remind me, along with a bandaged arm and now lots of pain. Thanks in advance for your help. Lee ps- I'm having to use the library's internet, so I'm only able to get on here for an hour each day, temporarily.

I was on a trip; overheated and turned the Cap off too fast and l likewise got the underside of My Forearm burned back in the 1980s.

When I got to where I was going; which was to visit a Person who was a Fire Fighter with the State Forestry Department I was told to put Aloe Vera Gel on it.
After I washed of the Noxema Cream I had bought to cover the burns I applied the Aloe Vera Gel and sure enough in about 30 minutes I got over 50% Pain relief. And, it is cheap also.
Since than it is a standard item in the Medicine Cabinet.

I sure someone has said this already if it happened suddenly before there was overheating it is likely a Head Gasket issue.
That would also pressurize the Coolant.

Phillytwotank · #8 08-20-2013, 09:53 PM

What is the recent service history for your car?

cooljjay · #9 08-20-2013, 11:15 PM

I always put a towel over the cap before I remove just in case there is any steam....only after a driver that is....cold in the morning not an issue....

Diesel911 · #10 08-20-2013, 11:38 PM

Quote:

Originally Posted by cooljjay

I always put a towel over the cap before I remove just in case there is any steam....only after a driver that is....cold in the morning not an issue....

Clearly prevention is better than being burned.

Like the OP I knew better but for some reason did not remember. It was likely I was too focused on getting on with My trip and not on what I was doing.

cooljjay · #11 08-21-2013, 01:54 AM

Quote:

Originally Posted by Diesel911

Clearly prevention is better than being burned.

Like the OP I knew better but for some reason did not remember. It was likely I was too focused on getting on with My trip and not on what I was doing.

I got a really good lesson on using a rag, my aunt bought a used van for cheap with a stuck thermostat....and of course she insisted on using it as a daily driver....so every 20 mins of driving we had to pop the cap and refill with water.....needless to say, I got really good at using s towel....and yes I know what that burn feels like

JB3 · #12 08-21-2013, 08:47 AM

can you post a video of the popping?

showme · #13 08-23-2013, 05:37 PM

Thanks for all the replies, everybody! I was just able to get back down to the library today, so I apologize for taking so long to reply. After looking in my trusty, but not always thorough, Hayne's manual, I started wondering about the injector possibility. Since I've been a bandage up to my elbow since the "incident", I'm not even really able to do anything yet under the hood, but I will be out there this weekend and trying these ideas on for size. (My wife told me I'd better not get any oil on the ace bandage over my dressings!

Infection is more what I'm worried about. But I will get some video, even if it's my cheap cell phone, and get over and use my brothers computer to post it, which is probably going to be tomorrow or Sunday. Once again, you guys have come to the rescue. It's been quite a while since I've had to do any repairs, (or had any money to do much maintenence), but this is my excuse to get out there and do some. Funny how the Temperature here in Missouri always manages to get into the 90's right when it's time for me to crawl under the old beater. Thanks again, and I'll get back with the video asap. I'd like to write more, but I got in here just as the library is closing.