A major short between the ears caused me to lose the majority of my coolant on my drive this morning. I pulled over after seeing mist coming from under the hood. Upper radiator hose was disconnected. My temperature gauge was reading just above the upper line on the sweep but not yet to the red. Engine sounded and performed fine up to me shutting it down.

I added about 2 gallons of water back into the radiator and reconnected the hose and finished the trip without issue. Oil on the dipstick didn't look contaminated. I'm hopeful my engine survived my mistake with no ill effects. Is there anything on it that I should check at this point?

Were you trying to save money on the recycling charge for used coolant?

A few years back, I patiently filled my diesel tractor with five gallons of gasoline from a five gallon container. Ya think I should have noticed the vaporous odors of gasoline? - Nope. I started to drive the tractor and noticed that the engine idle was fluctuating. I figured it out and shut down the engine. Fortunately, no harm was done. Stuff happens.

I think you are probably okay. I would monitor engine coolant for leaks and periodically check the engine oil condition for moisture. After you have re-established the coolant mixture ratio and the coolant level has stabilized, then monitor the overflow reservoir for normal changes in volume (cold engine vs warm engine).

TIP When the coolant exceeds 225°F the cluster will slam the needle to 240°F and trip the check gages light and chime. Since you never seen the Check Gages light you are fine.

No worse I was out a few years ago firewood cutting. Lost all the power steering fluid. I had ATF+4 in my toolbox I refilled with ATF+4 and finished the day and came home to flush that all out again. 504k miles still going.

Being out of a fluid is bad but replace with the wrong fluid can be better than no fluid at all. Just choose wisely.

Edited March 13Mar 13 by Mopar1973Man

Thanks for the pointers and assurances. i was driving at least 25 minutes before it dawned on me my mistake. It's amazing how efficient these Diesels are to not heat up any quicker than that.

Any easy way to check the Check Gages light and chime?

Another tip.

Always remove the thermostat from the head. This allows for a complete refill of the block and head space, so there are no hot spots or trapped air bubbles. Always drive the truck till the thermostat opens and then closes again by seeing the temperature of the coolant rise above the set point of the thermostat at least 10*F more. Then it should drop sharply to just below the closing temperature. This should purge the remaining air from the system. Just check the coolant level in the morning after it has completely cooled off again.

Thanks for that advice. I'll be removing the thermostat when I do the complete flush this weekend and will do the full fill before putting it back in.

Flushed the system per the article here.

I'm now emptying the water out from the radiator drain. There's mention elsewhere online about pulling the drain plug on the block, but not in this article, so I guess it's not critical. I couldn't find that block plug.

Regarding the radiator drain plug, I couldn't turn it by fingers alone. I made a slot in a 15mm nut and turned it with a ratchet enough to drain. I'd like to pull it all the way out to inspect and replace or lube that o-ring. Is there a stop that could be broken if I force it, or can I safely pull it the rest of the way out?

The radiator drain plug can be removed, but I probably would not do it. There a thick o-ring seal inside that the plastic petcock shaft fits through. The o-ring elongates because of friction while turning the petcock which in turn makes the petcock difficult to rotate. I find that if I rotate the petcock a little bit in each direction while opening or closing, it performs a little better. I have never broken one, but my brother-in-law has broken two.

To my knowledge, there is no drain plug on the engine block.

• John

Edited March 24Mar 24 by Tractorman

The two new radiators ive got have just a threaded plug now. Ive not seen a peacock style drain in awhile. Ive use nitrile o-rings out of my HVAC kit in the past for that repair. Little tricky to remove but the o-rings are easy to replace.

Is there a trick, or is it just a pain? Any risk? I've got plenty of o-rings.

That being said, mine's not leaking. I just want it to turn easier. Perhaps getting some lube up into the drain spout would suffice.

1 hour ago, Mopar1973Man said:

The two new radiators ive got have just a threaded plug now. Ive not seen a peacock style drain in awhile.

My radiator drain plugs are and have been the threaded plug style, too - I just incorrectly called it a petcock.

32 minutes ago, timsch said:

That being said, mine's not leaking. I just want it to turn easier

What I have observed is that antifreeze does not make dynamic o-ring seals slippery like oil does, in fact antifreeze is kind of grippy. This is one of the reasons why water pumps use mechanical face seals.

Years ago I took one of my drain plugs apart and cleaned it and after reassembly it didn't perform any better. I never really worried about the difficulty turning the drain plug because 99.9999% of its life is spent as a static seal and it never leaks.

• John

True, but the time it needs to be turned after years and it breaks then it's a problem. I'll get a q-tip and put some of my Parker o-ring lube on it if it's accessible as I think it'll be. Maybe it'll work....

5 hours ago, timsch said:

I'll get a q-tip and put some of my Parker o-ring lube on it

Then fill your radiator 50/50 (water/oil) so the o-ring will stay well lubed! .... just kidding!

I do understand that you are trying to make something better.

• John

If you want to refill coolant properly use a vacuum tool such as Snap-On sells.

If your cooling system is in a vacuum coolant will enter every crevice where the vacuum is, hence no air pockets. This is the only way we do it at Freightliner as air pockets can develop (such like in a egr cooler) that don’t necessarily burp out right away.

Refill method I use... First off, if the coolant system is drained, I always remove the thermostat. Then, as you fill the cooling system, it will push all the air up through the thermostat hole. This way, by the time the thermostat opens, there will be little air left in the head area.

1 hour ago, Mopar1973Man said:

Refill method I use... First off, if the coolant system is drained, I always remove the thermostat. Then, as you fill the cooling system, it will push all the air up through the thermostat hole. This way, by the time the thermostat opens, there will be little air left in the head area.

Just refilled it as you described. It took 3 gallons of coolant concentrate and only 1/2 gallon of water before topping the radiator. Surprised I didn't get more water from the flush out. No big deal though.

A squirt of WD40 up the drain hole got it moving much more freely. All's good (knock on wood). Hopefully I'll never make such a bad mistake again....

Did I miss something?

3 gallons of concentrate and only 1/2 gallon of water?

What happened to 50/50 mix? That's all I've ever done or even known for that matter. Even as a JD mechanic.

Total capacity is 6 gallons. It only took 3.5, so I assume there was still 2.5 left in somewhere. I found no block drain plug. Maybe there's air. I'll find out soon enough.

Oh I see what you were going for. Personally, I always either premix the concentrated stuff or buy premix what ever the case may be then add as needed. Yes it all gets mixed the same after pumping through a few times but, Im ocd and I always know I have the correct dilution. The thermostat fill @Mopar1973Man stated is one of the best ways to go and its super easy, I do this method myself.

I did fill with the thermostat out. As soon as water came up to thermostat level, I put it back in and attached the hose. Add more until the radiator topped off.

If I'd premixed, I'd be too low on concentration because what was already in the block was only water left over from the flush with my garden hose that I couldn't get out.

Edited 3 hours ago3 hr by timsch