Shes gettin hot

[ColMustard]

Well, ordered a windshield gasket from joe, good deal. The guys at the place must not have done it right, cause it's leakinh. Anyway, to add insult to injury, I had forgotten all about the heat issue last summer. So now, on extended drives, or a short burst of 90 mph, the guage gets pretty dang high just as soon as I get off the freeway. However, if im stuck in traffic, it will not overheat, what gives?. I already did the water pump, alls thats left is the oe radiator, or the head gasket. Ugggh. I notice after I hammer on it it looses a bit of coolant through the cap, (already replaced). Any suggestions, or comfort?

[1980sdga]

What are you calling high?  I'd probably get the radiator cap sorted. You shouldn't be losing coolant.

How bad is the windshield leaking?  I would take it back ASAP and have them check that out. Shouldn't they have checked it before it left the shop?

[Big_Richard]

when i had a new windscreen seal it leaked too.

it was leaking between the glass and the seal, i simply put a small amount of windscreen sealant the whole way around in the lip where the glass is and never had a problem since.

[jbrasile]

ColMustard,

I am sorry to hear about the leaky windshield, better have them sort it asap!

With regards to the overheating problem, did you replace the thermostat? How about the fan coupling, both those items may give you a similar problem as will a blocked radiator. It's interesting that you said the car does not overheat in traffic.

Start with the thermostat if that hasn't been done yet since it is the least expensive item, then the fan coupling, last I would have the rad cleaned professionally.

How high does the temp get on the freeway?

Tks,

Joe

[ColMustard]

Thanks all, did the cap, and thermostat. The car would overheat if it sat in one place idling, fan coupling? From past experiences with othet cars it seems to have enough resistance, also the aux fan never kicks on when it gets that hot, I used a ir thermometer to check the head and it was pretty close to what the guage said. The exact temp? Let me get a photo up, last summer it got way too close to the redline, cant believe I spaced it. Hot to me is 220 degrees

[ColMustard]

Dont get me wrong, it is within normal range, but it makes me nervous. It's gotten close to the danger zone before, way closer than this. I don't know.
Oh, and Major Tom mines leaking in the same place 

[jbrasile]

Well, it should stay right around 85-90 on the highway so you are running a little hot. I am assuming this picture was taken after a freeway run correct?

The fan coupling is 000 200 04 22, $304.00 list but it is probably ok because even if it was bad the temp should go down with the car moving which is not the case.

Try and  have the rad rodded and cleaned, it should solve the problem.

Tks,

Joe

[ColMustard]

Thank you joe, no thoughts on the headgasket?
I dont know. I've heard that noise again in the bottom half of the engine, but it was when I was about out of fuel, and usually always when cold. I almost hate to say this in this forum but the past week or so I've been running it pretty hard thinking if it's gonna go, I want it to go now. I'm willing to put another engine in, but I'm at a point right now where I want this car to be my daily. But if it did go, it would sit for quite some time. I just want to know whats going to happen before I start throwing all my wages at it. It, however, just keeps taking what I give it and frankly, I'm impressed as it seems to run better when I'm rough on it.
This weekend I am putting new shocks in the rear. One of them locked up, FULLY EXTENDED, has that happened to anyone else?

[1980sdga]

Just my opinion but...  I don't think headgaskets are a concern for the our old iron head engines.  I don't think it's a weak spot.  Unless you have water in the oil or something then I'd get the radiator cleaned/ clean the fins etc.  Maybe clean it out yourself and see if it helps.

I'd also take care of that coolant leak. The system has to maintain pressure to operate properly.

[Squiggle Dog]

I'm not sure if you've done coolant/citric acid flush, but if the coolant went through a long period of time without being changed (especially if the car sat for a while), the insides of the radiator and engine can get clogged up and this will greatly hinder the cooling.

It is recommended to use Mercedes-Benz coolant, or at least Zerex G-05 mixed 50/50 with distilled water. Some people still use the green stuff and say it is okay. The engine will run 10 degrees Fahrenheit cooler with the orange coolant and is great stuff. I have the orange coolant in my 1968 200 with 55 horsepower and drove it 2,000 miles last summer up through steep mountain passes. The temperature gauge didn't budge the slightest bit from normal operating temperature. And this is with no oil cooler, an old leaky radiator, etc.

I still haven't done a coolant flush on my 300SD yet, but may attempt it this weekend. It runs a bit hot like yours and has the green coolant in it.

[Squiggle Dog]

Oh, and I also went through the windshield replacement process on my last 300SD. I went through several different installers, none of which could get it to not leak horribly, even with the $130 OEM seal. In fact, I went back to Safelite 6 times and it still leaked! I ended up buying a tube of 3M bedding compound and fixed it myself. I think in the future I will install my own glass. No one seems to know how to install these correctly!

[jbrasile]

ColMustard,

I have never heard of a 300SD with a blown head gasket, it is possible but extremely rare.

Give the rad cleaning a try, but have it done at a good shop, it is not possible to do the job correctly at home.

It is hard to tell if your engine is about to go or not, the noise you hear could be related perhaps to a fuel shortage since you mentioned it happened again when you were almost out of fuel, has it always happened that way? I don't know enough about it but I have heard of something called injector slap, could that be the case here due to fuel starvation?

It looks like you have good oil pressure, your engine is not burning oil and you have good power, do you have a lot of blow by? a tell tale sign of excessive blow by is if your crankcase ventilation hose on the valve cover gets blown out of its tube often, but even then the engine will keep going.

Let's not be pessimistic here and go step by step. Try to solve the overheating issue, it really could be as simple as having the radiator serviced, and eliminate any coolant leaks, let us know how it goes.

I understand how frustrating it can get when you have a car that you really like and it seems that no matter what you do there is always something lurking around the corner to bite you. My 1980 450SEL did that to me for months, I even put it out for sale  3 months after I bought it, spent over 5k  and things were still going wrong... Finally I decided to bite the bullet, fixed stuff step by step and made into a super nice daily driver that served me for years and still does when I travel to LA, have the car since 1999 and will never sell it if I can help it...

Hope these words help you feel a little bit better.

Tks,

Joe

[jbrasile]

Squiggle, you are right on with regards to the cooling system being blocked after years of neglect from using the wrong anti-freeze.

The orange stuff is definitely the way to go.

Tks,

Joe

[ColMustard]

Thank you joe. It seems the loudest when its close to running out of fuel. Although I can still hear it when its not doing it loudly (one piston out of the five per revolution tick tick tick). Ive never changed the fuel filter(s) only have seen one. Im not too sure. Of all the cars ive driven, one with bearing noise and or rod knock didnt run as well as this. Idk I might be too much of a pessimist.
I fired her up today after a while of not running and I didnt hear that noise prominent enough for the average person to even hear it. It's probably nothing.
A full day tomorrow to try to cram in as much w 116 goodness as possible

[BWalker82]

Well, ordered a windshield gasket from joe, good deal. The guys at the place must not have done it right, cause it's leakinh. Anyway, to add insult to injury, I had forgotten all about the heat issue last summer. So now, on extended drives, or a short burst of 90 mph, the guage gets pretty dang high just as soon as I get off the freeway. However, if im stuck in traffic, it will not overheat, what gives?. I already did the water pump, alls thats left is the oe radiator, or the head gasket. Ugggh. I notice after I hammer on it it looses a bit of coolant through the cap, (already replaced). Any suggestions, or comfort?

Have you had the cooling system pressure tested?  The symptoms you are describing sound like that might be the problem.  Whilst at highway speed, the flow of air across the radiator raises the boiling point.  But when coasting from hwy speeds, sinking of the engine heat into the coolant, combined with a now lower boiling point (less cool air flowing & low/no system pressure to offset) causes the liquid temperature to raise uncontrolled.  Diesels, by nature, tend to run cooler because of the way the fuel is burned, not exploded, in the cylinder.

I say pressure test the system, esp the radiator, and then continue to drive the wheels off of it.  You should not have to worry about a severe overheating situation by pure nature of the engine's design, but you are in an effective 'limp home' mode and I wouldn't press her hard until she's patched up.

Most likely, your radiator is just coming apart at the seams.  It happens after 30 years... or 10 with any other make.