300E Heat Is Cold At Standstill - PeachParts Mercedes-Benz Forum

joel · #1 03-21-2005, 09:45 AM

When car is idling, no heat. If I rev or car is cruising, heat is hot. Any ideas.

89-300ce · #2 03-21-2005, 09:58 AM

Check and see if your heater pump is on. It's in the engine compartment at the passenger inner fender. You should be able to feel/hear it.

Jorg

meltedpanda · #3 03-21-2005, 10:01 AM

Sounds like an auxillary water pump issue?

joel · #4 03-21-2005, 10:45 AM

Quote:

Originally Posted by 89-300ce

Check and see if your heater pump is on. It's in the engine compartment at the passenger inner fender. You should be able to feel/hear it.

Jorg

Yes, it heats up but not when the car is not moving.

joel · #5 03-21-2005, 10:46 AM

Quote:

Originally Posted by meltedpanda

Sounds like an auxillary water pump issue?

where is this pump located?

meltedpanda · #6 03-21-2005, 11:00 AM

on mine it is on the inside firewall, but the reason I put a ? was because I did not know if yours had one.
The purpose of the unit on my 84 SD is to circulate coolant through the heater core (hot) while engine is at idle
Easy to check, pull wires add direct 12volt, listen for spin (or lack of)
Good Luck

A264172 · #7 03-21-2005, 11:00 AM

Quote:

Originally Posted by joel

where is this pump located?

Small cylindrical pump below the overflow tank... coolant line comes across the front of the block and up into the back of it then up on through the firewall. (on my 86)

joel · #8 03-21-2005, 12:52 PM

Thanks guys, I'll check it out.

Cheers

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