View Full Version : Driver Side Coolant Leak

11-19-07, 09:39 AM
Guys / Gals

Noticed over the weekend a big wet spot under our '99 Cat. I started freaking out thinking it was oil, but the feel and smell indicates coolant.

I've searched the forum here and have run across coolant leaks on the passenger side (which indicates the HBV/HCV), and towards the rear of the engine (which indicates the oil cooler). Could any of these devices be the culprit, or is there another valve on the driver's side that could be leaking? Please advise. Thanks a mil.


11-19-07, 04:01 PM
The Heater Bypass Valve (http://www.omegaowners.com/forum/YaBB.pl?num=1192574064) lives between the engine and firewall, under the scuttle panel. It could also be the Coolant Bridge (http://www.omegaowners.com/forum/YaBB.pl?num=1192574209) located at the rear of the valley under the intake plenum. Check the oil cooler cover plate while you're there. It can leak also though maybe not to the extent that the HBV will. Mine let go while the car was up on an alignment lift and I got to see the downpour up close.


11-26-07, 09:07 PM
Elvin -- Thanks. I looked up the price for a HCV via gmpartsdirect. It was running for $47.36. A far cry from $91.08 that the dealership would be charging.

However, it showed the valve only. Are there any other accessories I may need (i.e. clamps, hoses, etc.)? Thanks.

11-26-07, 11:10 PM
You could replace the hose clamps with Stainless Steel Worm Gear Clamps (http://www.smallparts.com/images/clamps/CHX-CL.jpg) but it shouldn't be necessary.


11-27-07, 05:04 PM
Okay -- I've been pouring over my service manual on how to install this HCV/HBV while I wait for it to come from gmpartsdirect. However, I don't see anything about replacing.

Are there any instructions out there for this novice to successfully (and safely) replace the HCV/HBV? Thanks.