91 LS400 HEATER/ coolant issues! HELP!
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Driver School Candidate
Joined: Jan 2009
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From: NY
91 LS400 HEATER/ coolant issues! HELP!
Hi All!
My heater takes forever to heat up. I changed the thermostat and made sure my coolant is not leaking or blowing any white smoke out the exhaust, but I keep having to top off the overflow bottle. The weird thing is , it seems to heat up faster at higher speeds , then gets cooler as I aproach a signal of get off the expressway!
What could be causing this & what else should I checke or test for furthur analysis. Where is the anti-freeze going???
The top and bottom hoses both get hot.
Thanks in advance for your response!
Paul
My heater takes forever to heat up. I changed the thermostat and made sure my coolant is not leaking or blowing any white smoke out the exhaust, but I keep having to top off the overflow bottle. The weird thing is , it seems to heat up faster at higher speeds , then gets cooler as I aproach a signal of get off the expressway!
What could be causing this & what else should I checke or test for furthur analysis. Where is the anti-freeze going???
The top and bottom hoses both get hot.
Thanks in advance for your response!
Paul
Thread Starter
Driver School Candidate
Joined: Jan 2009
Posts: 10
Likes: 0
From: NY
Thanks for replies!
I took out thermostat and tested in pot of boiling water and it is functioning properly, as was the old one I replaced!
What is the best way to bleed the system to remove an air pocket? Could the reservoir cap have anything to do with it??
Thanks!
I took out thermostat and tested in pot of boiling water and it is functioning properly, as was the old one I replaced!
What is the best way to bleed the system to remove an air pocket? Could the reservoir cap have anything to do with it??
Thanks!
Intermediate
Joined: Jul 2009
Posts: 445
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From: NY
B)Check to see if the heater valve is opening and closing correctly.
C) Check coolant reservoir for leaks that are merely evaporating under warm underhood temperatures. You may see tell-tale salt trails.
Colin
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Driver School Candidate
Joined: Jan 2009
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From: NY
A) Bleed system. The best way to bleed the system to remove an air pocket is to make sure engine is stone cold with the car level or on a slight upgrade. Crack loose the big bolt on top of the thermostat housing and if it does not weep coolant, take it off entirely so that you can carefully install coolant. Let it trickle in as slowly as it wants to. Once full, tighten that bolt to 14 ft/lbs or so (snug with a little yank), start the engine with heater on 85 fan on high with sunroof open, and run the revs from idle to 3,000 rpm or so. Keep an eye on the coolant level in the reservoir. It will draw down under high rpms (it will start to shoot upwards when you go back to idle as the thermostat opens if you dally). Get your coolant level to "cold" middle area at the higher rpm, and put the cap on securely. Drive the car in lower gears on surface streets with heater on around 3,000 rpm or so. Allow to cool and check reservoir level stone cold. These systems self-bleed, but you have to get some velocity in the water jackets and heater core.
B)Check to see if the heater valve is opening and closing correctly.
C) Check coolant reservoir for leaks that are merely evaporating under warm underhood temperatures. You may see tell-tale salt trails.
Colin
B)Check to see if the heater valve is opening and closing correctly.
C) Check coolant reservoir for leaks that are merely evaporating under warm underhood temperatures. You may see tell-tale salt trails.
Colin
Thanks!
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