heater problem - '95 LS400

[LS400GUY]

I know this topic had to be discussed in earlier forums, but my concentration is now on the heater control valve located on the eng firewall. I will list the series of events and would like to know if other Lex-heads had similar problems.

1. First of all, does the heater cont. valve ever get clogged up with crud? I've noticed some crud buildup around the inlet hose connection, my question is how does this happen? Is there enough crud in the cooling sys. that would cause this?

2. I first noticed the problem when the heat would turn cool whenever the car was idling, and would kick in again when the car started moving with the higher rpms. Which means if the hcv was clogging, the coolant needed higher rpms to be forced thru the hcv. Does this make any sense?

3. Can the heater contol valve be cleaned?

4. Should I run some radiator cleaner through the sys, would this help? Or should I simply replace the hcv?

Thanks much if anyone cares to share their experience with this issue.

Cheers,

LS400GUY

 

[Warm Pudgy]

i have a similar problem as my heater wont work unless im on the highway/higher rpms

only response ive gotten to my thread is did you check the thermostat? duh

 

[LS400GUY]

Hi warm:

Thanks for the reply. I've solved the problem! I found that my expansion tank was clogged up, which prevented the coolant from circulating throughout the system. I removed the coolant tank and thoroughly cleaned it out, it was clogged with silicone gasket sealant. You might have used it when the timing belt was changed - usually for the waterpump housing. You can easily tell if your coolant tank is clogged just by removing the bottom hose that leads to the engine, none or very little will leak out if its clogged. Secondly, remove the cap on the tank and see if there's any debri floating around, if so, that may be your problem. Once I cleaned the tank, I ran some radiator cleaner through the system, drained and refilled with coolant and now the sys. works like new. I hope this helps, but I would try this before replacing any expensive parts.

Cheers!

LS400GUY