Coolant leak

Tiny
BOOKBENZO
  • MEMBER
  • 2000 MERCEDES BENZ S430
  • 4.3L
  • V8
  • 2WD
  • AUTOMATIC
  • 160,000 MILES
I had my air worked on recently and a new air compressor went on and the system charged.

I my car is now overheating and leaking. My coolant visit workshop light comes on and then I notice the temperature rise up quickly past where it normally does.

There is a leak on the driver front side. Hoses are not leaking, radiator does not appear to be leaking at all, new radiator cap (old one was shot). I was sure the cap was it but it is not. What else could be causing my W220 S430 to be overheating but fast dripping water/antifreeze at the front driver side of the car?

I took off the valance, bleed the system as best I could. Fans appear to be working. I notice that the level was going down before but now it is not in the plastic tank reservoir.

Lost and I was trying to avoid the pressure test because they are. About forty to fifty dollars and do the job myself.

Any thoughts?
Monday, August 28th, 2017 AT 5:52 PM

9 Replies

Tiny
HARRY P
  • MECHANIC
  • 2,293 POSTS
Try the thermostat. If it is stuck shut, the car will heat up and then the coolant can start being pushed out of the overflow reservoir, appearing to be a leak.

If you want, you can borrow a pressure tester for your cooling system from AutoZone. There is a deposit, but you get it back when you return it. If you pressure test it, and find no apparent leaks, then it is most likely your thermostat.

Here is a guide on running the test: https://www.2carpros.com/articles/radiator-pressure-test.
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Monday, August 28th, 2017 AT 6:40 PM
Tiny
BOOKBENZO
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  • 5 POSTS
So I replaced the thermostat from Auto Zone (the big parts distributor around the country) and while it helped, it is still getting past 95 but not higher than 100 as I cut off the ac by then. Went to Firestone and they said I should not have bought the thermostat from there as they take too long to open and by then my engine has overheated. I am going to buy a Walher thermostat. But, what are your thoughts on a NAPA, Baps Wahler or Behr? Should I stick to the Walher?

He said my a/C fan should have two speeds, but mine has one speed. I never noticed, but there are universal fans on the engine attached to my radiator. He said it heats up because I do not have enough air pulling as my A/C fan never changes speed and there was low air even when the car was slightly higher than normal. After my review - true. Fans stay on but the engine does not spin fast and the A/C fan spins but does not have two speeds.

My question is? Should the A/C fan have two speeds and the engine have one speed?

I will be doing both these ASAP. Then I will be taking your recommendation for a pressure test as well.

Can you advise on those two items please?

You guys are awesome. Thank you for all the expertise!
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Thursday, August 31st, 2017 AT 4:31 PM
Tiny
BOOKBENZO
  • MEMBER
  • 5 POSTS
After checking and trying to price out the fans, I found out that I should only have one large fan to do the job and I have two. Does your information suggest that I should have only one fan as well? What years fans are compatible? Last seven of the VIN number are A054754? Very interesting. Maybe they put the universal fans on there because of the expense being much less. Maybe I should go back to OEM setup or just buy/replace those fans or get the one big fan? OeM is best I am sure. What is your take?

Again, thank you so much.
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Thursday, August 31st, 2017 AT 5:01 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 42,959 POSTS
I would installed an OEM fan to help with the over heating. did you get the coolant leak fixed because that would be the main cause of the problem. It sounds like a water pump problem.

Here is a guide to help you pin point the leak:

https://www.2carpros.com/articles/car-is-leaking-coolant

Please let us know what happens.

Cheers, Ken

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Friday, September 1st, 2017 AT 12:11 PM
Tiny
HARRY P
  • MECHANIC
  • 2,293 POSTS
As Ken stated above, go with OEM. Or at the very very least, something designed to be a direct fit (not something that has to be rigged or wired up to work). Get that taken care of, and see how it does after that. Let us know how it goes.
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Friday, September 1st, 2017 AT 2:45 PM
Tiny
BOOKBENZO
  • MEMBER
  • 5 POSTS
Thanks you guys. I fixed the fan. BIG difference in temp definitely with mid day in the AZ heat. Still overheating slowly but surely up too 100 oe slightly more. My car has never been this hot. I did decide to go with an agtermarket fan because there were universal sual fans in there. But I with with a derale 17" pulling 2400cfm. Love it. But. There was no signal from the ecm or something so the previous owner put those dual 12's in. I bought a 180 on 165 off temp switch and I love it. Only a couple things left.. Im going to test the water pump using the upper house squeeze technique, listen to see. If I hear noise at startup
I heard something last week when I put them in as I started the engine cold. Didnt occur to me that could be the sound of the water pump failure. I actually dont have a coolant leak, the leak is in the ac line. It actually decompressed while I was working on it and almost got freon face. But I was quick. IT still works, but I know the ac compressor could be adding load, but I dont want to see the thermostat move at all. It does go up without the ac on but my fans kick on now and keep it cool.

Since I have universal fans, im still going ro replace the coolant temp sensor because the computet needs the info inputed from it but the fans will turn on by themselves. Radiator looks good but maybe its clogged. I hope a waterpump will fix it so that the temp meter doesnt move in the car. Stays steady like it used it with the ac off. Thats what leads me to believe its the pump or radiator.

Thoughts? Both are affordable so I figd id buy a pump and flush the system again. Is 50/50 mix ok for s430 or so I need a certain colr for high miles?

Might do the radiator but I dont have the tools anymore for that. Only to do the pump. My car has a female torx hole with a nipple inside of it to release the tensioner. Any idea what size that is?

Or if I should do the radiator first
. The good part is I dont mind because in essence, itll only be cold here like 4 months and heat back up. My cooling system will be brand new hahahha just wanna so it in the right order. A shop said your fans only. Its not the fans only.

Open ears on this. You guys are awesome. Thx for reading this book.

BookBenzo
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Friday, September 15th, 2017 AT 4:55 PM
Tiny
BOOKBENZO
  • MEMBER
  • 5 POSTS
One othwr thing. I read that if your car overheats frequently it could be the coolant temp sensor. Mine doesnt output to my fans, but if it was faulty, could it. Make the temp rise even with the ac off or srick with the water pump. Replacement?
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Friday, September 15th, 2017 AT 5:03 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 42,959 POSTS
Yep the temperature sensor can cause the fans to come on too late causing the nine to over heat so You are on the right track for that. I think I would do the radiator in it as well becasue it can be block internally or externally.

Here are a couple guides and some diagram (below) to help you get the problem fixed.

https://www.2carpros.com/articles/how-to-replace-a-car-radiator

and

https://www.2carpros.com/articles/engine-overheating-or-running-hot

I believe it is a 35 torx for the tensioner arm.

Please let us know what happens and upload pictures or videos of the problem.

Cheers, Ken
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Saturday, September 16th, 2017 AT 2:31 PM
Tiny
HARRY P
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Sorry I'm a little slow getting back to you. Work has been busy busy. As Ken stated, go ahead and do the coolant temp sensor. It could cause the fans to come on late or not at all. As for the radiator, yes, you could replace it to take care of the core being clogged. Personally, I'd take the current one out and take it to a radiator shop to have it cleaned. They can take the tanks off and stick a rod through it, from end to end, clearing out each individual coolant passage.

But do the sensor first and see how it does. Then go from there. Good luck and let us know.
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Saturday, September 16th, 2017 AT 8:44 PM

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