E320 1995, Station wagon heating up? - PeachParts Mercedes-Benz Forum

Qamar · #1 04-26-2006, 04:53 PM

Today the outside temperature was 46.5 C in my region. For the first time the heat gauge of my car crossed 105 and it was quite near the red line.
The clutch fan is direct. Makes lot of noise but had always kept the car temp in between 85 to 90 C. Today despite that as stated above the heat gauge shouted up.
The radiator coolant is clear and there is no junk deposits seen in the coolant reservoir bottle. Had changed it a year back but not with the Merc recommended coolant.
The coolant reservoir bottle cap has never been changed. May be the cap is the main culprit and causing heat in the system. What cap number I should go considering the hot temperatures in my region.
Secondly if I remove the thermostat valve, will there be any reduction of heat in the engine. I had also changed the thermostat valve a year back. 75 C.
The heat gauge does come slightly down when the car is on the main highway but in city it comes near the red line with AC. Well without AC it is normal. Both the front fans are also working at their first speed.
A drop of coolant comes out from the upper hose of the coolant reseviour bottle which i am going to fix it tomorow.
Any advise to control the heat in the engine will be highly appreciated

mbdoc · #2 04-27-2006, 08:18 AM

ON that & most 1988 to 1996 MB's the aux fans don't come on HIGH speed until 107C....that isn't really that hot according to MB engine design.

michaelscooots · #3 12-29-2008, 05:00 PM

Hi everyone,

I found this old post. I'm having the same problem with me 1995 e320. Recently, I noticed that when I come off the highway into stop and go / residential driving, the temperature will shoot up to 100 plus. I can hear the fan motor come on and if I blast the heat the temp will come down to normal operating temp only when heat is running. When I go back up on the highway it drops to the normal range.

The head gasket was replaced a couple of years back as was the water pump. I haven't had any over heating issues until recently (past 2 weeks this problem first came up).

Thanks,
Michael

ds190 · #4 12-29-2008, 06:06 PM

Well, you don't say what you've done so far besides HG and water pump some years back. We'll assume it has new proper MB or G-05 coolant when HG was done. If more than two years ago, change it. Is the coolant level correct?

Replace the thermostat if not done with HG & water pump. How old is the radiator? Flush it recently?

michaelscooots · #5 12-29-2008, 06:41 PM

Quote:

Originally Posted by ds190

Well, you don't say what you've done so far besides HG and water pump some years back. We'll assume it has new proper MB or G-05 coolant when HG was done. If more than two years ago, change it. Is the coolant level correct?

Replace the thermostat if not done with HG & water pump. How old is the radiator? Flush it recently?

The water pump was replaced 18 months back (roughly 8-10K miles back) by my MB indie mechanic. He used the proper MB coolant as I recall having the discussion with him. Radiator was flushed at that time but may be original (not sure) / but I know it's not leaking. The coolant level hasn't really moved - it's at about half way up in the plastic overflow tank.

The head gasket job was done a little more than 2 years ago by the same mechanic.

Someone else suggested it could be the fan clutch. Is there a way for me to test this theory or should I just bring it in to the shop?

thanks,
Michael

cphilip · #6 12-29-2008, 07:26 PM

I don't have a lot of experience in this but I have read a lot here and on other forums that discuss temperatures and such. And what my recently obtained wagon does. And I consider this to be normal from all I can read on this and hear reported

It will run along at about 82 C all day long. At a brief stop light it will normally stay there or raise no more than 2 degrees C. If its a prolonged stop maybe 5 minutes or so it might raise up to 90. If it is stop and go from there and never gets much up to speed between multiple stops it might go to 100C. This is in fairly warmish weather. Say 60-70 F? With No AC on... in EC mode. But fairly close to that with AC on.

If I force it to heat up as much as possible, such as put the AC on and take it for a long run to really heat it up, and then park it and let it idle with AC on it will finally go to the Full fan mode (107C) after about 5-10 minutes of sitting still. But it will hold it there at 107 C if not drop it a degree and proceed no further up the gauge.

This is sort of what I was doing to them when I was looking at them to buy one too. Running hard with AC on and then letting them sit at idle with AC on. Noting temperature rise. Most of them responded this way. Most of them were hard to get hot enough to finally get to 107C but they all would eventually be forced to do so.

I imagine my slip clutch fan might be a bit worn and probably all the ones I looked at were too.... but it was fairly consistent except for one I looked at that ran a tad hotter than these others.

I could be wrong but that seemed normal to me. Its not been terribly cold here where I live recently so they all got tested in fairly mild weather.

michaelscooots · #7 12-29-2008, 08:18 PM

Yeah, this is definitely not normal for my car. I've had it a few years now and she is really over heating consistently whenever I drive her. I also have a 300TE and have never had this issue.

I think I'll take her to my indie next week to get it sorted out.

thanks,
Michael

Quote:

Originally Posted by cphilip

I don't have a lot of experience in this but I have read a lot here and on other forums that discuss temperatures and such. And what my recently obtained wagon does. And I consider this to be normal from all I can read on this and hear reported

It will run along at about 82 C all day long. At a brief stop light it will normally stay there or raise no more than 2 degrees C. If its a prolonged stop maybe 5 minutes or so it might raise up to 90. If it is stop and go from there and never gets much up to speed between multiple stops it might go to 100C. This is in fairly warmish weather. Say 60-70 F? With No AC on... in EC mode. But fairly close to that with AC on.

If I force it to heat up as much as possible, such as put the AC on and take it for a long run to really heat it up, and then park it and let it idle with AC on it will finally go to the Full fan mode (107C) after about 5-10 minutes of sitting still. But it will hold it there at 107 C if not drop it a degree and proceed no further up the gauge.

This is sort of what I was doing to them when I was looking at them to buy one too. Running hard with AC on and then letting them sit at idle with AC on. Noting temperature rise. Most of them responded this way. Most of them were hard to get hot enough to finally get to 107C but they all would eventually be forced to do so.

I imagine my slip clutch fan might be a bit worn and probably all the ones I looked at were too.... but it was fairly consistent except for one I looked at that ran a tad hotter than these others.

I could be wrong but that seemed normal to me. Its not been terribly cold here where I live recently so they all got tested in fairly mild weather.

michaelscooots · #8 12-29-2008, 08:20 PM

BTW, I have a few Vespas myself including a GS150 and 90SS. Lots of fun!

Quote:

Originally Posted by cphilip

I don't have a lot of experience in this but I have read a lot here and on other forums that discuss temperatures and such. And what my recently obtained wagon does. And I consider this to be normal from all I can read on this and hear reported

It will run along at about 82 C all day long. At a brief stop light it will normally stay there or raise no more than 2 degrees C. If its a prolonged stop maybe 5 minutes or so it might raise up to 90. If it is stop and go from there and never gets much up to speed between multiple stops it might go to 100C. This is in fairly warmish weather. Say 60-70 F? With No AC on... in EC mode. But fairly close to that with AC on.

If I force it to heat up as much as possible, such as put the AC on and take it for a long run to really heat it up, and then park it and let it idle with AC on it will finally go to the Full fan mode (107C) after about 5-10 minutes of sitting still. But it will hold it there at 107 C if not drop it a degree and proceed no further up the gauge.

This is sort of what I was doing to them when I was looking at them to buy one too. Running hard with AC on and then letting them sit at idle with AC on. Noting temperature rise. Most of them responded this way. Most of them were hard to get hot enough to finally get to 107C but they all would eventually be forced to do so.

I imagine my slip clutch fan might be a bit worn and probably all the ones I looked at were too.... but it was fairly consistent except for one I looked at that ran a tad hotter than these others.

I could be wrong but that seemed normal to me. Its not been terribly cold here where I live recently so they all got tested in fairly mild weather.

Arthur Dalton · #9 12-29-2008, 08:56 PM

Most often mis-diagnosed over-heat w/ac on that chassis is low refrigerant level.
The high side pressure switch on the drier/reciever does not get to cut-in b/c of slightly low refrig, so the car still has a/c operation, but no LOW FAN..this results in passive heat thremal load to radiator . By the time the coolant temp sensor reaches 107 cut-in , it is too late .
The tesy is to jumper the pigtail ends together at the high side sw and see if the low fans come on...if yes , then the low fan circuit is verified....now see if the low fan comes on when a/c has a thernmal loaad on it ...if No, you are low on refirgerant.
If you are in a high ambient climate zone, you can bridge the coolant temp sensor [ blue , 2 wire thermistor one at thermo housing] with a resistor to lower the 105/107 cut-in for high fan to approx 100C..this is a common mod on these dual aux fan seups where one needs the extra airflow.

cphilip · #10 12-30-2008, 05:06 PM

Quote:

Originally Posted by Arthur Dalton

...now see if the low fan comes on when a/c has a thermal load on it ...

Define what Thermal load it needs to turn the low speed on for me Arthur. How can I duplicate that situation? I can't seem to get the car to go over 82C today sitting there in the drive way. With AC on too. It is 60F ambient temp today here. Should they come on immediately or do they have to see more load than that? Mine are not low speed functioning when at 82C with AC on. And I think they should be running immediately when AC is put on. Is that correct? So that relay is bad or the level is low. At first I was leaning to the relay due to the fact the AC puts out very well but I read a few thread says this is wrong way to think about it. Could still be it is just slightly low enough to do exactly this. And that is more likely the issue here. Something to look into first I guess.

They will come on at near 90-100C (not sure when but have observed them both running at one point) in low and they will come on High (no mistaking that noise when they do that) at 107C and then they hold temp there, if not drop it a tad. This is all with AC on or not. So I know from that the Fans are fine so I imagine I should look into the AC relationship even though I have not seen any problems yet... but then again, it is winter and not harshly hot this time of year. Good time to go into that I guess.

Added on edit, From pictures I have seen of this Bridged Resistor, it appears they have just lodged each end of the resistor lead into the plug? Of course I would need to know which two too shove it into if that all it is....

Arthur Dalton · #11 12-30-2008, 06:19 PM

I will write a short tutorial on thernmal load conditions and low fan activation..you can then have a better understanding and most likey be able to answer your own questions with that info.

Low aux fan is A/C acitvated ONLY.. the relay is fused and it is located in the relay box. [ behind the fuse box...there are two..one for low and one for hogh fan] The sensor that triggers the low fan relay is the HIGH PRESSURE switch located on the reciever/drier, at the condenser. There are two sensors located at the condenser ..the one for aux fan cut-in is the one with the 6" Pig-Tail wires coming out of the sensor...NOT the one with the spade connectors.
So ..do the low fans work is the first question when one has a hot running engine w/ac ON.
The first thing we want to do is test the integrity of that fan circuit..this is quite simple to do by simply jumping the two pigtail wires together [ thereby by-passing the high pres sw] ..this should result in a low fan activation if all componenets in the fan system are OK [ fan/relay/fuse /droppping resistor/etc]... Once that is verified , then you are now down to only two possibles ...the sw is bad OR there is not enough high pressure to trigger the sw cut-in spec. This test only requires Key ON.
This is where Thermal Load comes into play...The fans are NOT designed to come ON just b/c you are using a/c...it is an AUX FAN and it is designed to only come on when the condenser pressures gets HIGH and the system is being TAXED, which is caused by a HIGH TERMAL LOAD..meaning, if one is using a/c on a cool day, don't look for a fan activation b/c one is simply not being called for..but if the ambient temps are high, along with humidity , you now present the system with a taxing condition. [ thermal Load]..the results are the sw closes , bringing on the fans , and that added air-flow across the condenser will keep the pressure in check... If one does have a fan activation on a hot day, then he does not have a low refrigerant condition..simply b/c a low refrigerant level will not have the capacity to pump the high side pressure up enough to trigger the sensor.
There is an eye-sight on your reciever/drier..if you see lots of foam, you are low.
If you want to test a low fan at low ambients , you can also cover the front of the car to help heat it up some...but the actual test would be to take a high side pressure reading to see if the system gets to sw cut-in spec when you have a hot day...if no, then possible refri level..if yes, then you know the sw is bad.
In your case you have verified low fan when it is hot out, so I don't suspect either condition, but watch for low fan on a hotter day/condition...

I would also do the blu sensor bridge, as the lower cut-in is a cool mod...they [ Benz] claim 107 is of no dnager to this car, but I don't like to see it and they were known for head gaskets to begin with, so anything above 100c is not to my likings............... [I think they made the claim b/c they has plentyof Complaints]...I use a cabin sw on all my Benz b/c I am a dash gauge driver and it allows me to get a jump on the system before the sesnors can act...it also allows me the preference of using the low fans , unlike the high fans that the bridge resistor mod activates. But that is choice........That cabin toggle simply jumper across that same high pressure/pigtail sw I mentioned earlier..just bring a two wire lead into the cabin from that sw and you are done...$2 well spent.
>>and lastly, addressing your condition..I wpuld split the rad and condenser a little and clear out the crap in between the two..you will be shocked when you see the debris in there and that is a common cause of your condition.
Aux Fan airflow means nothing to a plugged up condenser...it is the radiator that suffers the passive heat from the condenser and the results are the coolant temps getting to 107 trigger...107 trigger should be a rare occurance on that engine.

cphilip · #12 12-29-2008, 09:18 PM

Quote:

Originally Posted by michaelscooots

BTW, I have a few Vespas myself including a GS150 and 90SS. Lots of fun!

You have two of the most coveted scooters in the world. The SS and the GS!

Arthur Dalton · #13 12-29-2008, 10:20 PM

Yeah...In the South the resistor bridge works well....
Some guys also use a toggle/cabin sw across the low fan sw too...that way you have a manually controlled fan anytime you want it...guys that tow boats or do a lot of traffic jams and stuff use that ...either one only costs a couple of bucks..

As far as your 107 condition, you fail in your post to mention if the low fans are coming on w/ac..that is the point I was making.

cphilip · #14 12-29-2008, 09:15 PM

What would you call "over-heat" Arthur?

If things were forced to do so in maximum load like I described and they eventually hit 107, went into Full Fan mode, and held there, dropped a bit or at least didn't climb above 107 wouldn't that be normal?

The fan on mode at 100C surely does sound like a good idea to me in the South here.

cphilip · #15 12-30-2008, 07:30 PM

Got it. Will reread that a couple times to be sure but sounds like I am jumping the gun because I could not make the fans come on today.

Alright. Will have to locate these things and verify them all to be sure. I didn't see any bubbles in the Dryer window. Did look for that.

I am going to be taking the car to the Indy next week for tranny fluid (don't have a good place to do it) so I just might as well ask him to check the pressure anyway though. But by that time I should have a good weather day to do some of this other checking.

Thanks again Arthur.