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Two random questions

Mastiff

Mastiff

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Question 1: How do you suppose my coolant level in the radiator could be low, even though there is plenty in the overflow? It was only about an inch down, but still. All I can think of is the overflow system itself malfunctioning. The radiator cap is recently replaced.

Question 2: Do you think Mobil 1 oil has a shelf life? The Mobil site says 5 years, but they might just be covering their butt or encouraging us to buy more. I have a quart 10+ years old that I'd kind of like to use right now, but am hesitant.
 
1. None of my GM vehicles from this era are set up to recirculate, just overflow

2. Have a lawn mower? I might be hesitant
 
I have some Mobil 1, Valvoline and Quaker State that’s at least 35 years old that I’m trying to get rid of too, although I’m using it in my chainsaw as bar oil, still seems fine. Don’t know if I’d be willing to save a few bucks on something that has the potential to do a lot of damage money wise.
 
rampage said:
I have some Mobil 1, Valvoline and Quaker State that’s at least 35 years old that I’m trying to get rid of too, although I’m using it in my chainsaw as bar oil, still seems fine. Don’t know if I’d be willing to save a few bucks on something that has the potential to do a lot of damage money wise.
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Seems like I have way too much stuff already in the bar oil category, especially since I don't chain saw very often anymore. Point taken on the money. I guess it's more about the waste of it or something.
 
Mastiff said:
Seems like I have way too much stuff already in the bar oil category, especially since I don't chain saw very often anymore. Point taken on the money. I guess it's more about the waste of it or something.
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Your local auto parts store will gladly take it off your hands and put it in their recycling barrel. Not wasted - recycled. :waytogo:
 
skunked said:
Why risk using old oil?
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Just to not waste it I suppose. And I just wanted to discuss it. Manufacturers put expirations on everything. I noticed an expiration date on a container of salt once.
 
rampage said:
Your local auto parts store will gladly take it off your hands.
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That's just recycling though. I'm not worried about getting rid of it. It's a waste in the sense of it (probably) being perfectly usable.
 
If you have a stock overflow bottle where the hose from the radiator neck hooks up to at the bottom of the bottle, it will recirculate. The key items for it to work properly is a functioning correct radiator cap and the radiator full of coolant to the neck.

The only thing making the coolant move into the overflow in or out is expansion and contraction. As the coolant gets hot it expands and any extra will bypass the cap and go into the bottle. As the system cools the coolant contracts (ie takes up less space) and creates a slight vacuum in the radiator and allows some coolant to be pulled back from the overflow bottle to maintain the level in the radiator.

If the coolant is too low in the radiator, all the expansion happens within the radiator itself and can't push out past the cap. As it cools the level goes back down but can't pull any more out of the overflow bottle due to the lower level.

The thing you see when the radiator level is too low is the level you have set in the overflow bottle never moves. It stays and never fluctuates. It should change as the temp of the engine goes from hot to cold and back again.

If you have a generic bottle where the hose from the radiator hooks up to the top without any pipe to the bottom, it will not circulate.
 
ZooMad75 said:
If you have a stock overflow bottle where the hose from the radiator neck hooks up to at the bottom of the bottle, it will recirculate. The key items for it to work properly is a functioning correct radiator cap and the radiator full of coolant to the neck.

The only thing making the coolant move into the overflow in or out is expansion and contraction. As the coolant gets hot it expands and any extra will bypass the cap and go into the bottle. As the system cools the coolant contracts (ie takes up less space) and creates a slight vacuum in the radiator and allows some coolant to be pulled back from the overflow bottle to maintain the level in the radiator.

If the coolant is too low in the radiator, all the expansion happens within the radiator itself and can't push out past the cap. As it cools the level goes back down but can't pull any more out of the overflow bottle due to the lower level.

The thing you see when the radiator level is too low is the level you have set in the overflow bottle never moves. It stays and never fluctuates. It should change as the temp of the engine goes from hot to cold and back again.

If you have a generic bottle where the hose from the radiator hooks up to the top without any pipe to the bottom, it will not circulate.
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Yeah, mine is a recirculating system. The question is how the radiator could get low in the first place without a pretty major leak. With a very small leak/usage it ought to still recirculate as usual, just drawing more from overflow than it put in during expansion. I suppose if the truck sits a lot, it could leak while off enough to nullify the overflow system as you describe. I have no visible leaks though.
 
Mastiff said:
Yeah, mine is a recirculating system. The question is how the radiator could get low in the first place without a pretty major leak. With a very small leak/usage it ought to still recirculate as usual, just drawing more from overflow than it put in during expansion. I suppose if the truck sits a lot, it could leak while off enough to nullify the overflow system as you describe. I have no visible leaks though.
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Evaporation. Internal leak within the engine, as in a head gasket leak or cracked head. Another symptom of a head gasket/cracked head would be overpressurizing the cooling system with combustion pressure. That pressure will overcome the rated pressure on the cap and push coolant into the overflow and possibly puke out of it. Look for signs of coolant pushing out of the outlet on the top side of the bottle if that was the cause. A weak cap would give the same symptom too. I say that knowing you got a fresh cap on there. Still worth testing to make sure it holds the correct pressure though. I've seen bad caps right out of the box that don't hold pressure.
 
I'd be checking the oil for signs of antifreeze just to be safe. Is oil level higher than it should be? You can hold a lighter to the oil on the dipstick. If it "pops" it has water in it. Probably not the problem but worth checking.
 
Far as I knew oil never "went sour",and the old adage "oil never wears out--it just gets dirty" was considered truth..that is why they recycle oil and sell it,it just gets filtered to the max and a new dose of additives put back in it..

I've used "old oil" that dated back to the late 70's..
My dad used to buy Sears "Spectrum" 10W-40 by the case and I came across several unopened quarts in the basement a few years ago...

I used it in my tractors and wouldn't have been afraid to put it in a car's gas engine,but I didn't want to put any in my 6.2 Diesel as it wasn't diesel rated for soot control..

We had many cases of decades old oil at some of the parts stores that no one ever bought--mostly straight grades like SAE 10,20,and 30 weight...we used it in our own vehicles and the delivery vehicles,never had any oil related problems..

One time though a friend found some old Castrol 20W-50 quarts he bought decades ago,when he poured some out,it looked like oil at first,then a white goop came out like Elmer's glue at the bottom 1/3 of the bottle..

He decided to chuck it out rather than risk damage,but some websites claim all you need to do is shake it up,its the additives that settle out and form the white goop...I'd just assume spend $4 a quart for new oil you know is good though,unless you had an old leaky oil burner of an engine you could care less about..
I suppose condensation could form in a plastic bottle over time,but that would boil off quickly and not be likely to harm anything..
I would think synthetic oil would have a practically unlimited shelf life..
 
Ive got 2 cases of mobile 1 full synthetic 0w20 that are at least 8-10yrs old, wondering the same thing. Hate to just recycle it when it was ~$9 or $10 per quart. If it was just 1 quart that would be easier pill to swallow.
 
I wouldn't think synthetic would go sour in only 8-10 years,if it looks OK I'd use it..
More important is the rating for what service the oil is to be used for..
Many have become "obsolete" in recent years..

I went to Walmart today intending to buy a 2 gallon jug of diesel oil (their own brand) ,I had been using 15W-40 of various brands,whatever I could get on sale,their brand is about $10 a gallon,or just under $18 for a two gallon jug,but I was thinking about trying SAE 30 for a change seeing its summer and hot out..and GM reccomends it for any temps over 32 F,it says SAE 30 "preferred"..

But the SAE 30 Walmart had,has a "CF" rating,which according to this chart ,was introduced in 1994,and is now "obsolete" for engines after a certain date,(2000 something)--but it would be OK for my 6.2 that was designed to use diesel oil with a CC-CD rating back in the 80's,and the CF oil covers that application...its "better" than any oil they had that far back..

But I waited on buying any oil,I have a case of SAE 30 Wolf Head oil I bought for my small engines that has a SN/CF rating,I may try that instead..I'm curious to see if it runs any quieter with SAE 30 than 15W-40..might boost the oil pressure a bit too..
I'll put 15W-40 or 10W-30 back in it come winter ..

Walmart was also completely out of stock on lawn tractor batteries--was going to bring a core in and buy one today,glad I didn't..as usual I go shopping,and come home empty handed..I only go there for those 2 items,I rarely ever shop there for anything else despite it being only a 1/4 mile away..

Here is the oil rating chart ..
Layout 1
 
If i could hijack a little:

Do most GM cars, not just trucks, say before 1996-ish, have a 3/8" overflow hose going to the overflow tank? Ok, maybe not the 4 cylnders etc.

If not, why not?
 
Mastiff said:
Yeah, mine is a recirculating system. The question is how the radiator could get low in the first place without a pretty major leak. With a very small leak/usage it ought to still recirculate as usual, just drawing more from overflow than it put in during expansion. I suppose if the truck sits a lot, it could leak while off enough to nullify the overflow system as you describe. I have no visible leaks though.
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If coolant level is going down with no visible leaks, its burning Does it smell when running on cold start? If in garage does exhaust cause a burn in your eyes?
 
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