How Long Without Coolant?

[Kenshiro]

Now, I am not an imbecile suggesting the car be run or even started without coolant, but a title suggesting that helps draw people in to yell at such an imbecile, and gets people to read. Here's my situation:

I'm doing a largish overhaul of the car and part of it is a rebuild of the coolant system. I need to drain the coolant to replace the radiator, expansion tank, etc., but some of the parts (notably the 3-way hose for the Euro expansion tank) are going to be a couple weeks to a month to get here. I'd like to get as much of the work done as possible ahead of time as I'll be out of the country for a while at the beginning of next year, so this raises the question: if I drain the coolant and leave it drained for that period of time, how long before I have to worry about the coolant passages in the block starting to rust over?

The head, thermostat housing, and the majority of the other metal parts are aluminum so no worries there, but I'd rather not have to flush the coolant twice to ensure no rust has built up in the iron block from atmospheric oxygen. Coolant residue will hold off oxidation for a while until it drains off the passage walls I suppose.

[Albertan]

If the coolant system is able to be closed, then rust formation would be less.
I assume it will probably be open, in that case surface rust will form until the moisture is gone. I wouldn't worry too much as it would only be surface rust.

[99MPower]

I start cars all the time without coolant in them. Thats not a problem. You can run them up to 30-45seconds with no issues.

I do it when I'm testing engine work before I spend another 1-1.5hours putting everything else back in, coolant in, bleeding, etc and THEN finding a problem.

I've been told this is not an issue by a pro engine builder. Just dont abuse it

[mmark.]

It won't hurt anything to sit dry/empty. That is, as long as the car is not stored in an area where the floor sweats a lot with changes in ambient temp.
Do not install the new water pump until you are set to complete the job.


m

[Volf]

I start cars all the time without coolant in them. Thats not a problem. You can run them up to 30-45seconds with no issues.

I do it when I'm testing engine work before I spend another 1-1.5hours putting everything else back in, coolant in, bleeding, etc and THEN finding a problem.

I've been told this is not an issue by a pro engine builder. Just dont abuse it

+1

Only I've never run it more than 20 seconds or so.

[scoobiedoo2029]

id wrap the coolant connections in tape to seal them up while its sitting. less about surface rust an more about crap getting in there like a mouse.... i got a euro m30 from a junk yard and its coolant passages where orange, a good flush and alls been well for about 30k miles. but i left a radiator outside once and a i noticed it smelled weird behind the garage, picked up the radiator an dead chipmunk fell out of it...

rodents want to drink coolant.

[das borgen]

I start cars all the time without coolant in them. Thats not a problem. You can run them up to 30-45seconds with no issues.

I do it when I'm testing engine work before I spend another 1-1.5hours putting everything else back in, coolant in, bleeding, etc and THEN finding a problem.

I've been told this is not an issue by a pro engine builder. Just dont abuse it

up to a minute is perfectly fine

20 seconds is all you need really to weed out any lingering problems before you commencing buttoning up

without oil..... 0 seconds, MAX

[fsmtnbiker]

The total lack of reading comprehension in this thread is really entertaining.

Letting the car sit with no coolant will be fine. The surface rust that forms won't be detrimental to the system, especially if you flush it once. I've dropped engines in that have been sitting in junkyards for years with no coolant, and had no problems. If you can close up the system (tape, etc.) that will further reduce your need for concern. Also, if you just drain the radiator, and don't pull the plug in the side of the block, the water level will actually stay up high enough that the iron block will be completely full still.

[Kenshiro]

The total lack of reading comprehension in this thread is really entertaining.

QFT. And thanks for the input.