Write-Up: Flushing Radiator Coolant

Subject: Re: Write-Up: Flushing Radiator Coolant Mon Nov 02, 2009 2:36 pm

deekster_caddy wrote:

Some of the old V8s even have a bypass to keep coolant flowing around the block... (think buick 350 and 455) but why did they stop doing that?

I think that it's stupid in the summer, when I want ice-cubes to come out of the A/C, but the answer to your question is that we don't have shut-off valves in the heater hoses anymore. Ergo, the heater core loop provides the recirculation that the hose on the front of the engine used to...

_________________
97 Riviera L67 - Desert Sandstone - Gutted AB Lid, Kool Blue AF, 180* SuperStat, Hogan 3" DP, ZZP 3.6" MPS; Sensa-Trac struts, Rockford-Fosgate 6x9's; Annoyance-Fixes: Express-Down delete, Full-time juice to Power Port, BRP-power to Glovebox lite, Brake-to-Shift delete, Console-compartment lite, Seat/Mirror Memory in any gear.

69 Wildcat Convertible, 430" QJet - Burgundy/Black - P/Win, P/Seat, P/Ant, Tilt, Cruise, Remote Trunk, Rallyes, AM/FM Mono!

Subject: Re: Write-Up: Flushing Radiator Coolant Mon Nov 02, 2009 3:01 pm

AA wrote:

With drilling holes, warm-ups can take longer (increasing engine wear), and you may never get up to proper temperature (also increasing engine wear). The better way, imo, is to tune your fans to cool the radiator properly, and letting the t-stat do its job.

I also don't believe the engine gets a shock when "all that water in the radiator finally rushes in". As mentioned, the t-stat doesn't open suddenly; it opens very slowly, letting a small amount of coolant through.

I understand how a hole would help keep air from building up behind the t-stat, but how exactly does it "purge air back out of the system"? Where does the air go?

I do think a very small hole drilled in the t-stat wouldn't cause any problems, but it also won't do much to help performance.

You'll note that none of the reasons I gave were for hot cooling performance, I'm not talking about that kind of flow. And a pair of sub-1/8-inch holes are not going to make the engine "never get up to temperature".

As far as the opening of the stat, surely you've stood around with the engine running, the radiator cap off, waiting for the thermostat to pop so you could top off the coolant... Growing up in a garage, I've done it scores of times. When that 'still' water behind the stat finally gets heated by conduction instead of flow, the stat does open rather quickly. If it had a wide temperature range, it wouldn't be able to keep the operating temp in such a narrow one. And remember, when you're driving, the coolant in the radiator is being kept chilled by the rushing air.

For purging, you got me on the semantics. I should have written "helps when you are purging air from the system." I simply meant that when you're trying to purge the system, air, like water, will flow out to the radiator before the stat opens.

We'll just have to agree to disagree on this one, at least until I can see how it runs at Tahoe in mid-winter. ride

_________________
97 Riviera L67 - Desert Sandstone - Gutted AB Lid, Kool Blue AF, 180* SuperStat, Hogan 3" DP, ZZP 3.6" MPS; Sensa-Trac struts, Rockford-Fosgate 6x9's; Annoyance-Fixes: Express-Down delete, Full-time juice to Power Port, BRP-power to Glovebox lite, Brake-to-Shift delete, Console-compartment lite, Seat/Mirror Memory in any gear.

69 Wildcat Convertible, 430" QJet - Burgundy/Black - P/Win, P/Seat, P/Ant, Tilt, Cruise, Remote Trunk, Rallyes, AM/FM Mono!

Subject: Re: Write-Up: Flushing Radiator Coolant Mon Nov 02, 2009 3:13 pm

Eldo wrote:

but the answer to your question is that we don't have shut-off valves in the heater hoses anymore. Ergo, the heater core loop provides the recirculation that the hose on the front of the engine used to...

Never thought about that. Ah Hah moment.

_________________
98 Riv, 102K Miles, EBC, LS1 Ft.Calipers, STB, Addco Rr Sway Bar, 180* stat., SSAC Headers, HF Cat, 1.9's,
105# springs, MPS 3.4, DHP tuned by the Deekster.

Subject: Re: Write-Up: Flushing Radiator Coolant Mon Nov 02, 2009 4:02 pm

Quote:

When that 'still' water behind the stat finally gets heated by conduction instead of flow, the stat does open rather quickly. If it had a wide temperature range, it wouldn't be able to keep the operating temp in such a narrow one.

I don't doubt that the t-stat responds quickly; I'm saying it doesn't go straight to open from closed. It opens gradually, so it's not at full flow when it first begins to open. It's not a "pop" thing, nor is it an on/off thing. There's a 10 degree range in which the t-stat operates (between 190-200ºF).

At 190º, the thermostat cracks open, as designed. It starts letting coolant pass at a slow rate at first, then opens wider as temps increase. In 40ºF ambient temps, it takes 5 minutes for the engine to warm up to 190º. Drilling holes will delay the t-stat in cracking open. Obviously the larger the holes, the longer the delay. My point is, if your holes are small enough that they don't matter much, then they really don't matter much (there are guys out there drilling multiple 1/4 holes in their t-stats).

_________________

Subject: Re: Write-Up: Flushing Radiator Coolant Mon Nov 02, 2009 4:21 pm

Do the "jiggle pins" in most t-stats performs the same function as a hole drilled into the flange?

_________________

Modern "Muscle"

1996 Supercharged Riviera, Black Cherry Ext., Burgundy Int., over 200K

Subject: Re: Write-Up: Flushing Radiator Coolant Mon Nov 02, 2009 4:43 pm

I think the jiggle pins do the same thing as drilling holes, but I don't see them in "most" thermostats, only high performance racing types.

_________________

Subject: Re: Write-Up: Flushing Radiator Coolant Mon Nov 02, 2009 4:45 pm

I've never noticed that pin in any of the thermostats I've bought in recent memory.

_________________
98 Riv, 102K Miles, EBC, LS1 Ft.Calipers, STB, Addco Rr Sway Bar, 180* stat., SSAC Headers, HF Cat, 1.9's,
105# springs, MPS 3.4, DHP tuned by the Deekster.

Subject: Re: Write-Up: Flushing Radiator Coolant Mon Nov 02, 2009 5:00 pm

AA wrote:

I think the jiggle pins do the same thing as drilling holes, but I don't see them in "most" thermostats, only high performance racing types.

The t-stat by "motorad" that is recommended for the Riv, has 'em.

_________________

Modern "Muscle"

1996 Supercharged Riviera, Black Cherry Ext., Burgundy Int., over 200K

Subject: Re: Write-Up: Flushing Radiator Coolant Wed Nov 04, 2009 11:53 am

I've seen these pins on certain thermostat designs for installation "clocking" which means that if oriented in any other way, coolant flow can be affected.

Subject: Re: Write-Up: Flushing Radiator Coolant Wed Nov 04, 2009 5:13 pm

BKRIV wrote:

I've seen these pins on certain thermostat designs for installation "clocking" which means that if oriented in any other way, coolant flow can be affected.

Could be. I did notice that the second stat pictured is asymmetrical... The 'guts' are offset to the right.

_________________
97 Riviera L67 - Desert Sandstone - Gutted AB Lid, Kool Blue AF, 180* SuperStat, Hogan 3" DP, ZZP 3.6" MPS; Sensa-Trac struts, Rockford-Fosgate 6x9's; Annoyance-Fixes: Express-Down delete, Full-time juice to Power Port, BRP-power to Glovebox lite, Brake-to-Shift delete, Console-compartment lite, Seat/Mirror Memory in any gear.

69 Wildcat Convertible, 430" QJet - Burgundy/Black - P/Win, P/Seat, P/Ant, Tilt, Cruise, Remote Trunk, Rallyes, AM/FM Mono!