Before I install inline thermostat I am thinking about changing out coolant. Is this poisonous to touch? How many drain cocks are on radiator. With only 1/8s hole in chev thermo I am wondering about how I can change coolant in future. Any help will be appreciated maybe even a picture of this drain cock and how it opens. Plyer's going to work. FYI my heater is cold right now not up to snuff.

Assuming you're talking about a CRD, the coolant (should be/is) HOAT-based. Zerex G-05 seems to be the most common aftermarket cooland that's HOAT. It's very similar to normal ethylene-glycol coolants in that it's only poison if you ingest it, but it's not very good for your skin (rather drying, etc.). latex/nitrile gloves and some good hand cleaner should keep your extremities happy. Don't leave it around where pets or wildlife would be able to get to it...unless you have a rat problem in your crawl space or something. Also typical, it's not good for long-term exposure to plastics or painted surfaces, so be sure you follow up the work with a liberal application of an appropriate soap and plenty of cool running water to rinse down anything the coolant touches.

I did the job yesterday, so it's fresh on my mind. the drain (1) is on the left (looking from front to rear) side of the radiator near the lower support just above the front torsion bar. You can attach some tubing to help keep things clean, but doing so obscures access to the screw plug (ironically). It's plastic and I don't know what you're "supposed" to use, but I used channellock pliers very carefully. You don't need to turn it more than about 1 full turn and there's an indexing mark at the spot where it should be fully "closed" so note where that mark is when you open or close it.

with the overflow tank closed, open up the drain. It'll come slow, but the level will drop in the tank. After it appears empty, open up the cap to drain the rest of the engine. The manual says 11.8 qts, I think, but I only got out about 10. I imagine it would require pulling plugs in the block to get ALL of it out.

After you do the t-stat, close everything back up and fill the overflow tank. It'll gurgle and some will drain down. Repeat till it stops doing that. Then go for a short drive so the temps get up to t-stat opening numbers. The level should drop a bit and you can fill it some more. Just be careful to:
- Don't open the overflow cap with the engine running. It tends to mess things up since it's a pressurized system.
- Make sure that the "cold fill" line is what you're shooting for as you go through a few run/cool cycles topping things off. If you get any fluid in the right side chamber after the engine has fully cooled, it means you have too much in there and you can open up the tube leading from that chamber and let that part drain out. It should remain empty under normal operation.

Dan

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2005 Silver CRD Limited
245/75R16 GoodYear Duratracs
Fumoto drain | ProVent CCV Filter
Stanadyne FM100 filter | Cummins fuel pump
GDE Eco | SEGR | BoulderBars | FrankenLift | Frankenskids

See viewtopic.php?f=98&t=56398 for easy tool on that lower plug. Things go faster if, on a cold engine, you open the lower radiator drain then open the radiator cap on the plastic tank on the firewall (what Dan refers to as the overflow tank - NOTE this plastic thing functions as the top of our radiator, hence the pressure cap, and the overflow tank, hence the side chamber). Once the plastic tank drains open the cap on the upper passenger side of the radiator to vent the system and complete draining.

That cap on the upper passenger side of the radiator can be removed to speed final drain by turning to 4:o'clock and pulling straight up, reinstall is the reverse. Full system capacity is not know for certain but IMHO the FSM and Owner's Manual goofed on metric conversion and true capacity is 12.5L (all sources are consistent on this) which is 13.2qts but in any case there is physically no way to drain all the fluid short of pulling the lower radiator hose (a serious big pain) as its lowest point is below the block and radiator. If you want all the old fluid out you can try to suck it out with a vacuum per viewtopic.php?f=5&t=56486&p=628305&hilit=citric+flush+acid#p628305 ; multiple fill and drains with clean water (ca. 7 cycles as stoutdog did); or what I plan to try which is a Prestone flush and fill kit http://www.amazon.com/Prestone-AFKIT0-U ... 648&sr=8-1

I'd add 6-6.5 qts Xerex G-05 to get near to 50/50 mix. If you leave that upper passenger side cap on the radiator off the system fills quickly. Once you get the Xerex in there slowly add water until the upper cap overflows then close it which minimizes the air left in the system. Top off the sytem until the reservoir is just over 1/2 full. As Dan notes drive and add fluid as needed (I found if I filled to like 3/4" above 1/2 I did not need to add any additional coolant).

For future fills do it the same way. That in-line tstat and its 1/8" hole doesn't change anything as, on a cold engine, the OEM tstat will be closed anyway and you are refilling via the coolant bypass system so the only influence the in-line will have on that refill is that last tiny little bit at the top of the system which will mostly be filled by fluid backing into the OEM tstat housing but if you are concerned you can "burp" the system by squeezing the upper radiator hose.

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Sold to LOST member my 05 Ltd, GDE Stg II turbo + TCM tune, SunCoast TC w. Transgo kit, Steiger window regulators, Samcos, Fumoto valve, 2nd gen filter head with Lub. Spec. bleeder, Hayden clutch & 11 blade fan, inverted spare, P-1 battery, BF Goodrich Long Trail TAs, Etecno1 glow plugs, timing belt at 50K miles/8 yrs

My temps went up little bit but my heater is still cool warm and then goes away. The radiator plug just screws out counterclockwise to open. Very little coolant drained out I used one gallon xerex g05 5050 to refill, drain is really slow. If I want to have dealer do flush with the machine does this make any sense? I may tackle Vicous heater next to run some water through maybe some CLR or Radiator flush. Then might even try heater core if I can locate 2 hoses there is a lot information on clearing these out on Youtube with air or garden hose. Not having heat sucks and is first vehicle I have ever owned with this problem hell my 85 bmw never had an issue. With inline mod I have noticed gauge at one click to left from center. Motor stayed hot underneath for long time, infact I took rad cap off and wussshhh locked it, is this boiling temps?