I am in the need of opinions or past experiences to answer a question about something that recently happened to my truck. I recently had a new alternator installed on my truck by a trusted mechanic. I picked it up Friday and drove it probably 30 minutes to my house and parked it for the weekend. On Monday morning, I went out and cranked it up and let it warm up for a few minutes before I left to take my daughter to school. When I went back outside, prob. 6 or 7 min later, I noticed it was idling up and down at a rate of about once every 1 to 2 seconds. I got in and it noticed the temp gauge was moving toward the red and no heat was coming out of the vents so I shut it off immediately. My first thought was thermostat but not sure. I came in and got on Yotatech, which I have been lurking on for a year or two but never posted on, searching for an answer. I noticed someone said that one time this happened due to the coolant in the rad. being low. So I checked it and to my dismay the radiator appeared to be bone dry. Long story short, I topped it off with 6 qts (more or less) with water and this cleared it up. My question now is, would the mechanic have to drain the radiator some or completely to change out the alternator. The truck was on the rack so I figured they would have to remove the lower hose to get it off. I called him and he said he didn't think the guy that worked on it had to but he would check. For the past 2 days, I have noticed a leak at the drain cock on the radiator that seems to drip slowly and form a puddle about 12 inch in diam. which I never ever noticed prior to the alternator swap. I want this to be the problem so bad b/c it will be easily fixed otherwise I know the downside to disappearing coolant and it is never good. NO other leaks were found and the oil does not appear to be mixing with the coolant or vice versa. Sorry this is so long and I will try to keep future posts to the point.

1989 p'up 4wd extended cab, 22RE with 251K on original.

Thanks

 

sounds to me like the mechanic probably didn't have to drain it, but maybe he did? who knows?

I would assume that there was a slow leak and you didn't see it or something. As unlikely as that is, it's a possibility, keep an eye on it and see what happens, and carry some jugs of water with you as cheap insurance,

oh, and do a search on here about burping the radiator or burping the heater core, as you will need to do that if you have any trapped air in your coolant system, which is also very likely seeing as how wasn't any coolant and you didn't get any heat, but that is most likely not the cause of your problem

the only possibility i can think of, for why this happened after the mechanic worked on it (other than him draining it and not refilling it) is that maybe he bumped or broke something that caused a leak (either while you drove it home, or while it was sitting, or while it was warming up three days later)

that, or you have antifreeze gnomes running around

 

I would have to agree b.miller that your slow leak is the problem. You are probably loosing water more quickly when the system is up to operating temperature/pressure. I guess it is possible the mechanic accidentally damaged your radiator, but those situations can be tough to prove.

Good luck and let us know what you find out.

 

It is very difficult to remove a 22RE alternator with the lower hose in place. Its possible, but in terms of a shop doing it, it makes more economical sense to drain the radiator, remove the hose, and pull the alternator out the bottom. Sounds like it was drained, and either the draincock was not tightened, or has since began leaking. Its possible that if the O-ring was lost or rotted, it will not seal.

 

btw I would suggest a radiator pressure test

 

We pulled the lower hose when we did our alt.

 

Thanks for the input. I am going to attempt to try to drain and flush the radiator this weekend b/c it prob. needs it anyway. The water to coolant ratios are screwed up now anyway. I will pick up a new drain plug and o ring and thermostat as well and see how things go.

 

Ok, I ended up going to every parts store in town looking for a new drain plug because I have isolated this as being the culprit for my coolant loss...at least I am keeping my fingers crossed. Didn't find one but noticed while I was out driving around that at the rate it was dripping at one point, it is highly possible that it just drained out without me ever noticing. I tightened the crap out of the existing drain plug for the time being, topped off the rad. with 50/50 and made sure there wasn't any air trapped the best I could.

I will keep an eye on it for a few days and let ya know.

 

Ok, it turned out to be the drain plug. When I finally drained the radiator and took it out the plug looked as if it had been removed with some pliers or due to age became brittle and broke a piece off which was allowing a little bit of coolant to leak through the tube. Now that has been fixed, what is the most common problem for my engine to be running rich. I know from doing a search, the O2 sensor might be first thing to change. Is there anything else that I need to do or try first? Thanks for your help.