Time for a new radiator for my 84 300SD?
 

Hello to all From Corvallis Oregon!
Yep I just got out of my 300SD... After a 9 hour drive to Corvallis to see my mom for the weekend. On the way up the I-5 I had several times when I thought the car was going to over heat. It never did, but I didn't like that feeling. The car was running about 110C all the way up the Central Valley in CA in 40-42C temperature out side. then when I climbed up to Lake Shasta the air cooled down to 28-30C and so the car cooled to around 100C, but then when I climbed the Siskiyou Pass the car was on the verge of over heating. I was creeping up the hill fallowing a semi to keep from over heating... and then when I came down into Ashland the tempture was down to 80C... and the car only went over 100 2 or 3 times on the rest of the trip, going over Grants Pass I thought it was going to get hot again, but only got to 110C.

So, I have to go back to Sacramento on Sunday. I don't have to work on Monday so I’m planning on making the trip at night.

I think I may need a new radiator, because 3 weeks ago I did a cooling system flush and it helped, but not enough.

What do you guys think? I know radiators are around 300 bucks... is there anything else I can do? Would it be cheaper to get my radiator boiled? Or maybe a Pick'n'pull radiator?

Nik

have you changed the thermostat recently? that might be a better place to start

Also, during the flush did you remove the radiator and clean all the leaves/debris out from between it and the condenser?

Where do i go from here?
 

Well, I'm back in Sacramento.
Before leaving Corvallis I pulled the termostat. And I drove at night, and I over heated at the top of Siskiyou Pass.

what do I need to troubleshoot next?

When you flushed, did you get a bunch of crap? If so, you might want to do a more agressive flush with a citric acid solution. Also, a water pump with the wrong impeller is a possibility. Also, how's your fan? A long climb up a mountain with the A/C on puts a big heat stress on, and if you are not moving that fast you don't have very good cooling if the fan clutch is not right.

No AC on during the whole trip. I've been having an issue withath making the car to hot... so i just left it off.

I've never changed the water pump. can the water pump go bad? I mean other then the bearing?

and i'm not sure how to test the fans?

when i did the flush i got a lot of rusty water out but no chuncks.

If it's original from '84, I'd change it for PM anyway.

Called Napa, they will have a new water pump for me to pick up tomorrow.

I also called the Mercedes Dismantler here in sacramento... 150 for a radeator...

$150 for a used radiator????? Is that the same outfit in Ranch Cordova that wanted to charge me $50 to remove a little air/oil separator off a 240D? Plus $15 for the thing! Plus shipping!?
Sheesh I bought a brand new one for $68 at the stealership! Thats what I think of Silverstar!:mad:

A brand new Nissens Radiator 1265003503 goes for $195. No shipping! PM me.

I would never buy a used radiator unless I KNEW how old it was and if/when it had the fluid changed. If it has metal end tanks you can have it rebuilt for ~$100. Get yours rebuilt or get the new Nissen. To answer your previous question: the impellar on the water pump can corrode and/or start spinning freely on the shaft.

Also, if you are replacing the radiator and water pump, certainly replace the coolant cap and thermostat. Also consider replacing every single cooling hose.

I picked up a new thermostatin corvallis. I got a new cap when I did my flush at the begining of summer (it apeard to be working fine when it was boining over... held pressure when i pulled over... and a few second later opend up on its own and boiled all over). i'm going to replace the water pump on friday. if there is any problems after that i'll be getting a new radiator.

are you saying your running without a thermostat?:eek:

I missed that. The thermostat controls and directs flow through the radiator. I'm 95% sure your #1 problem is that without a thermostat, less coolant is going through your radiator. I wouldn't change the water pump unless you know it's bad. And another flush might really be worth it, flushing through the drain plug in the block and using the correct coolant.

I disagree.

The thermostat offers a significant reduction in the available pipe diameter simply do to it's design. It cannot flow anywhere near the amout of fluid than an open hose can flow.

So, if the thermostat is removed, the flow past the point where the thermostat would live is significantly increased.

The loss of flow to the bypass line is not large enough to offset the increase in flow due to the removal of the thermostat.

Every member who has removed the thermostat has observed a reduction in engine temperatures.

I'm still waiting for someone to overheat a 617 with the thermostat removed.


The problem with many of the radiators is an accumulation of debris between the fins on the outside of the radiator. It must be removed from the vehicle and thoroughly cleaned with compressed air, a water pressure washer, a condenser cleaner, or a combination of these methods.

If you hold the radiator up to the sun, you'll see the debris that has accumulated in the fins. All of it must be removed for proper airflow.

Chasing the water pump and replacing the thermostat is usually a waste of time and money.

Brian, next chance you get, look at the cutaway views and associated description of coolant flow in the FSM for the 617 engine. It is complicated - I design flow testing machinery for a living and it took me a little while to understand it. HOWEVER, AS THE PICTURES AND DESCRIPTION SHOW, REMOVING THE THERMOSTAT WILL REDUCE MAXIMUM COOLANT FLOW THROUGH THE RADIATOR. It even goes on to say that removing the thermostat to increase coolant flow is false reasoning, due to the removal of the bypass restriction.

It's been a few years and thousands of posts, I suppose we had to disagree at some point.;)