1998 E300 no heat, - PeachParts Mercedes-Benz Forum

d-zel · #1 10-22-2006, 04:39 PM

I just replaced the radiator, bleeding went fine, but no heat in the cabin. Anyway, this is the first time this year that I am using the heat, so I don't know if it worked before. About 2-3 months ago I replaced the blower regulator on it, maybe this has something to do with it?...Anyone can help me on this?

Matt L · #2 10-22-2006, 04:48 PM

Either you still have air in the heater circuit from draining the system, or your duovalve is bad. The fault could also lie in the pushbutton module, but this seems unlikely. I vote for #1.

d-zel · #3 10-22-2006, 08:17 PM

Quote:

Originally Posted by Matt L

Either you still have air in the heater circuit from draining the system, or your duovalve is bad. The fault could also lie in the pushbutton module, but this seems unlikely. I vote for #1.

How do I get the air out and where is the duovalve. How do I check the duovalve to see if it's working? Thanx, Joe

F18 · #4 10-22-2006, 08:46 PM

Quote:

Originally Posted by d-zel

How do I get the air out and where is the duovalve. How do I check the duovalve to see if it's working? Thanx, Joe

Joe, I replaced my radiator last fall. It did take me a while to get the whole system air free.....there is no bleed valve on my 98 E300TD like I've had on some of my other vehicles. Its suppose to be self purging/bleeding. It is but it takes its time doing it!
Run the engine at high idle with the pressure cap off the over-flow tank and the heat setting at high. ....it does not matter if fan is on high or not.
Watch coolant level and top it off if needed. After engine has reached operating temp. put the cap on the over-flow tank and take the vehicle out for a highway spin with heat controls still on high....open your windows if needed. Park it and when cool check coolant level again. If fluid level dropped and or the heat started working then air finally was purged from the heater core.
Some guys pull the top hose partially off the radiator to purge the system before the coolant gets to hot to handle...but that just creates a mess!
Good Luck!

d-zel · #5 10-22-2006, 11:18 PM

Quote:

Originally Posted by F18

Joe, I replaced my radiator last fall. It did take me a while to get the whole system air free.....there is no bleed valve on my 98 E300TD like I've had on some of my other vehicles. Its suppose to be self purging/bleeding. It is but it takes its time doing it!
Run the engine at high idle with the pressure cap off the over-flow tank and the heat setting at high. ....it does not matter if fan is on high or not.
Watch coolant level and top it off if needed. After engine has reached operating temp. put the cap on the over-flow tank and take the vehicle out for a highway spin with heat controls still on high....open your windows if needed. Park it and when cool check coolant level again. If fluid level dropped and or the heat started working then air finally was purged from the heater core.
Some guys pull the top hose partially off the radiator to purge the system before the coolant gets to hot handle...but that just creates a mess!
Good Luck!

I will try this tomorow, I hope this is going to solve the problem. Thanx, Joe

d-zel · #6 10-23-2006, 11:59 PM

Quote:

Originally Posted by F18

Joe, I replaced my radiator last fall. It did take me a while to get the whole system air free.....there is no bleed valve on my 98 E300TD like I've had on some of my other vehicles. Its suppose to be self purging/bleeding. It is but it takes its time doing it!
Run the engine at high idle with the pressure cap off the over-flow tank and the heat setting at high. ....it does not matter if fan is on high or not.
Watch coolant level and top it off if needed. After engine has reached operating temp. put the cap on the over-flow tank and take the vehicle out for a highway spin with heat controls still on high....open your windows if needed. Park it and when cool check coolant level again. If fluid level dropped and or the heat started working then air finally was purged from the heater core.
Some guys pull the top hose partially off the radiator to purge the system before the coolant gets to hot to handle...but that just creates a mess!
Good Luck!

Looks that all the air is gonne out of the system, and still the same so probably the duovalve is the problem.

nhdoc · #7 10-24-2006, 07:40 AM

Quote:

Originally Posted by F18

Joe, I replaced my radiator last fall. It did take me a while to get the whole system air free.....there is no bleed valve on my 98 E300TD like I've had on some of my other vehicles. Its suppose to be self purging/bleeding. It is but it takes its time doing it!...

My '98 has a purge plug up on top of the block and it's mentioned in the WIS. I think it said to open the plug and while filling watch for coolant to come out of the hole (which never happened) so I filled from the tank and removed the plug and filled from there too. It took quite a bit of coolant through that little hole as I recall but it probably helped eliminate an air pocket up top by doing this.

d-zel · #8 10-24-2006, 10:21 AM

Quote:

Originally Posted by nhdoc

My '98 has a purge plug up on top of the block and it's mentioned in the WIS. I think it said to open the plug and while filling watch for coolant to come out of the hole (which never happened) so I filled from the tank and removed the plug and filled from there too. It took quite a bit of coolant through that little hole as I recall but it probably helped eliminate an air pocket up top by doing this.

Thank you, I'll take a look at that to. Joe

d-zel · #9 10-25-2006, 12:40 AM

My mechanic unpluged the electrical socket that goes into the douvalve and I let it stay like this for a whole day. He said it needs to relax. (funny). I have pluged it back in today and gradualy regained the heat to normal. I also checked the coolant level and it's slightly lower than it used to be yesterday, maybe it took some time for the system to get the air out. So ,I don't know what it was, the duovalve was stuck or something or the air in the system. Anyway, thank you guys, you are so great. Joe

Matt L · #10 10-25-2006, 09:20 AM

Quote:

Originally Posted by d-zel

My mechanic unpluged the electrical socket that goes into the douvalve and I let it stay like this for a whole day. He said it needs to relax. (funny). I have pluged it back in today and gradualy regained the heat to normal. I also checked the coolant level and it's slightly lower than it used to be yesterday, maybe it took some time for the system to get the air out. So ,I don't know what it was, the duovalve was stuck or something or the air in the system. Anyway, thank you guys, you are so great. Joe

Probably air in the system. Unplugging the duovalve should let it run in the wide-open position.

d-zel · #11 10-25-2006, 10:21 AM

Quote:

Originally Posted by Matt L

Probably air in the system. Unplugging the duovalve should let it run in the wide-open position.

I did not have heat with the valve unpluged, it started after I pluged it back in.

F18 · #12 10-25-2006, 11:14 AM

Quote:

Originally Posted by nhdoc

My '98 has a purge plug up on top of the block and it's mentioned in the WIS. I think it said to open the plug and while filling watch for coolant to come out of the hole (which never happened) so I filled from the tank and removed the plug and filled from there too. It took quite a bit of coolant through that little hole as I recall but it probably helped eliminate an air pocket up top by doing this.

Marty,
I unscrewed that plug to but it did not seem to do anything so I replaced it right away. Good to know that WIS refers to it as a "purge plug". I'll work with that a little more the next time I change the coolant.
Cheers

nhdoc · #13 10-25-2006, 02:53 PM

Quote:

Originally Posted by F18

Marty,
I unscrewed that plug to but it did not seem to do anything so I replaced it right away. Good to know that WIS refers to it as a "purge plug". I'll work with that a little more the next time I change the coolant.
Cheers

It doesn't do anything but if there's air in there and not coolant it means you haven't filled it all the way to displace the void. IIRC the WIS says to fill the system until you see coolant come out of that hole, but with mine it never did so I simply poured the coolant into it until it was filled from there...it took a good pint or so to displace the air in there.

I have learned (the hard way) that you never, ever want to run the engine with a big air void in the head...that can be one costly coolant drain/refill, trust me.

F18 · #14 10-25-2006, 06:03 PM

Quote:

Originally Posted by nhdoc

My '98 has a purge plug up on top of the block and it's mentioned in the WIS. I think it said to open the plug and while filling watch for coolant to come out of the hole (which never happened) so I filled from the tank and removed the plug and filled from there too. It took quite a bit of coolant through that little hole as I recall but it probably helped eliminate an air pocket up top by doing this.

I just forced air and coolant through by squeezing the top rad. hose like a pump until it was firm with fluid as it warmed up. And yes....you do not want an air pocket...it can cause a nasty hot spot that can easily warp heads.
On my last diesel the K1500 TD it had an actual purge valve on the thermastat housing which made changing and replacing coolant easy.
You could hear the air whistle through it when you bleed the system and when clear coolant finally came up out of it you were done and you closed it.

EdzBenz · #15 03-09-2008, 01:53 PM

Guys,
I have been trying to find the purge plug on the top of my engine block. Can anyone help direct me to finding this plug? I just bled my system and have tons of air in there. Thank you for any help.