View Full Version : I think my HGs are gone

06-05-10, 09:36 PM
Today was a nice warm day, great day to take the Caddy out for a ride. Except that the day started with a Check Coolant Level message, that goes away after a minute of driving. A friend that was following me said that there's a decent amount of white smoke from the exhaust when I go WOT. So I stopped for about an hour, and fired it back up, there's wisps of white smoke from the exhaust that weren't ever there before. It gets a bit higher on the temp gauge when going uphill now than it ever did before. For the 22000 miles I've had the car, I never saw the gauge get past noon, now it's at that first hash mark going uphill. Now I know that first hash mark can be normal, but I've never seen it get that high before, and the white smoke can't be good either. What do you say? I'm gonna have a block test done soon.

06-06-10, 12:36 AM
Run a block test before doing anything to save yourself $$$$.
The white smoke is a telltale sign of impending HG problems, though.
Good luck!

06-06-10, 07:04 PM
The block test was fine, I squeezed the bulb for about a minute before the Caddy puked a bunch of coolant into the tester and all over the ground. The fluid in the tester was blue until that happened.

06-06-10, 08:30 PM
Have you pulled the coolant purge line off the side nipple on the reservoir, stuck it into the filler neck, and checked for a steady flow at idle ?

The sudden "puked a bunch of coolant" sounds like either poor coolant circulation or an air bubble stuck somewhere in the system - heater core, maybe - that core is part of the coolant bypass system and is a necessary part of coolant circulation during warmup.

06-06-10, 11:24 PM
The purge line is clean, I know that much. I'm taking it that the Caddy shouldn't spew coolant out of the recovery tank, even if the engine and coolant are warm? I just sealed the tester in the tank, and squeezed the bulb for a minute, and all of the sudden, there's coolant shooting out the top of the tester. Will all the blue fluid turn completely yellow if there's an HG leak? I'm starting to suspect poor circulation, given this negative block test. BTW, the coolant hasn't been changed since Nov 2007. I know, it's been too long.

06-07-10, 10:01 AM
If the engine (coolant) is warm/hot there should be 2 - 3" of airspace at the top of the coolant reservoir. BUT, be careful with a hot engine: the Northstar thermostat begins at 188 and is fully open at 206. Unpressurized 50/50 coolant boils at about 216. Without A/C fans go to SLOW at 224, so it's possible to idle for a while and boil over when nothing's wrong except the pressure cap is missing: it's that cap, and that cap alone, which raises the boil point of coolant to 265.

When you're doing a block gas test you want the A/C ON - fans run in SLOW and the engine won't boil over from extended idling.

BUT, if it boils over again during idle tests, you're looking at a coolant circulation problem.

Cough up the $140 and have a GM dealer do a complete coolant exchange.