Flushing coolant

[Lzybmbjj30]

I'm convinced that my engine is overheating do to needing the coolant flushed and replaced. My mower would stall and start overheating when going up hills with the pto engaged. The engine has two coolant plugs to drain. one under the radiator and one on the block. The one under the radiator has a lot of coolant that comes out. The one on the block nothing comes out. It' bone dry even when I fill the radiator with water to flush it out. I have heard that if the previous owner used stop leak it can cause that drain to get plugged up and you can use a screwdriver to remove the plug.

Do I need to drain both plugs or will that leave coolant in the block?

 

[85Hokie]

You are convinced? It have a temp gauge? Or any other way to determine it is too hot? Stall directly related to overheating? Water pump working correctly? Belt tight?

First - the fact that NO coolant comes out of the block is a very bad thing! Not familiar with your model - does it have thermostat?

I would first empty everything the best you can - run a weak acid throughout, 50% vinegar will work, get it hot, empty - repeat. THEN flush with water for about 4 more times .......

then fill with water - using infrared thermometer - determine the temps at the block at upper hose, upper radiator and more importantly the lower part of radiator at the lower hose neck.

You could have a stopped up place in block - if so - I would think the machine would quit all together! Could be as you said - a blocked drain hole.....

report back with your findings........actual temps will help you a lot when looking for the problem

 

[Lzybmbjj30]

I do remember seeing coolant in the block holes when I replaced the head gasket so it's definitely in there. Another thing is that I checked the oil and there appears to be too much.

 

[D2Cat]

When you drain the oil put it in a clean container and determine if it simply has too much oil add into the crankcase, or if there is water/antifreeze or diesel in the oil.

Get the drain petcock out of it and get the block all cleaned out as 85Hokie advised. Then get all the crud off the petcock hole so the thing works next time you want to drain it.

 

[Lzybmbjj30]

Some time during the summer not knowing what I was doing I just put water in the radiator and never flushed the system. It boiled over once several weeks later and has had the overheating issue ever since.

 

[North Idaho Wolfman]

When you had the head off did you have it professionally magnafluxed to check for cracks?

Isn't the overheating why you tore it apart in the first place.

 

[Tooljunkie]

Some time during the summer not knowing what I was doing I just put water in the radiator and never flushed the system. It boiled over once several weeks later and has had the overheating issue ever since.

Water transfers heat better than coolant. The fact you needed to add something to rad tells me that coolant was going somewhere at that time.
If its getting into oil than either gasket was damaged during install, or head/block could be cracked.
A pressure test will tell you if its leaking, but will require disassembly and professional testing/inspection to find source of leak.

 

[Lzybmbjj30]

I never checked the head for cracks nor the block. If you remember I posted pictures of the original head gasket and head and block. Everyone on a previous forum said that it looked fine. No one said that the head gasket was blown or anything. I checked the head for warping and couldn't find any.

I'm just wondering if the overheating is due to not flushing the system back when I aded coolant to the system. I forgot to mention that after I added the water I realized I needed 50/50 coolant and put that in instead without flushing it. Is it possible it's overheating because of a water to antifreeze ratio? Maybe something in the cooling system like the water pump is rusted and it's clogging the flow between the radiator and the engine.

Also I don't think that the oil is mixing with the coolant. If that were the case wouldn't the oil be a brownish almost caramel color or almost like mayonnaise? The oil is just kind of a thick black texture.

 

[85Hokie]

I never checked the head for cracks nor the block. If you remember I posted pictures of the original head gasket and head and block. Everyone on a previous forum said that it looked fine.

VIEWS ON A COMPUTER SCREEN CANNOT TELL IF THERE ARE HAIRLINE CRACKS IN THE HEAD OR BLOCK.

No one said that the head gasket was blown or anything. I checked the head for warping and couldn't find any.

LITTLE EASIER TO SEE A BAD GASKET - BUT MANY A GASKETS HAVE BEEN BAD THAT LOOKED GOOD!

I'm just wondering if the overheating is due to not flushing the system back when I aded coolant to the system. I forgot to mention that after I added the water I realized I needed 50/50 coolant and put that in instead without flushing it. Is it possible it's overheating because of a water to antifreeze ratio?

WATER - STRAIGHT WATER - IS MUCCCCCH BETTER AT REMOVING HEAT THAN ANY 50-50 MIX!!!!

Maybe something in the cooling system like the water pump is rusted and it's clogging the flow between the radiator and the engine.

POSSIBLE AND A REAL GOOD FLUSH (HOT) WILL HELP THAT

Also I don't think that the oil is mixing with the coolant. If that were the case wouldn't the oil be a brownish almost caramel color or almost like mayonnaise? The oil is just kind of a thick black texture.

TRUE - MOISTURE IN THE OIL WILL GIVE A MILKY COLOR - AS FOR THE OIL, THICK IS A RELATIVE TERM - AND BLACK MEANS IT IS DOING IT'S JOB!

I would suggest that you take the temps at all points on the engine with the infrared thermometer and get back to us!

 

[D2Cat]

You start the post with, "I'm convinced that my engine is overheating...."

Do as 85Hokie keeps suggesting, get an infrared thermometer. Then get actual measurements at the radiator top and bottom hose and of the block.

It's so much easier to have facts when diagnosing a problem! It helps eliminate the urge to begin replacing parts.

 

[Lzybmbjj30]

Ok thanks I will try that.

Also just so you know this only happens when going up hills and with the pto lever engaged. I was riding it the other day and it stalled when trying to go up a hill. The engine seems to run forever with no problems when the pto isn't engaged.

 

[Delmar]

Your G1900 has a temp gauge; does it work? It also has a warning horn that goes off if the temp gets dangerously high - it's LOUD.

Your description of symptoms doesn't sound like overheating to me. Sounds more like a fuel delivery problem. If the engine dies under heavy load, with no other indication of overheating, I'd start checking fuel flow through filters (there are 2), injection pump, and injectors at the head.

 

[85Hokie]

Ok thanks I will try that.

Also just so you know this only happens when going up hills and with the pto lever engaged. I was riding it the other day and it stalled when trying to go up a hill. The engine seems to run forever with no problems when the pto isn't engaged.

What is being used on the PTO? your MMM? are you sure the belt is correct and not binding anything? All the spindles greased well?

Loading the PTO works the engine pretty good - most of the time, you'll find a lot of problems more quickly when placing the load on the engine for a bit of time - overheating is just one that can be found quicker working the engine.

If you go up the hill - PTO not engaged - no problems pulling the hill? You going up hill in Low or High gear(s)

There still seems to be too many intangibles to deal with, need to narrow those that do not have any bearing on the situation!

 

[Lzybmbjj30]

Your G1900 has a temp gauge; does it work? It also has a warning horn that goes off if the temp gets dangerously high - it's LOUD.

Your description of symptoms doesn't sound like overheating to me. Sounds more like a fuel delivery problem. If the engine dies under heavy load, with no other indication of overheating, I'd start checking fuel flow through filters (there are 2), injection pump, and injectors at the head.

I have never heard anything like a horn when it appears to be overheating. I've also never seen the temperature gauge do anything to indicate overheating. I do know that when the engine starts smoking it wells up from the whole thing.

This is the original video I posted several months back before I ever took it apart.

https://www.youtube.com/watch?v=_Morjp2dOYE

 

[85Hokie]

"I have never heard anything like a horn when it appears to be overheating"

It is not really a "horn" it is steam that is forced through a "whistle" and when the radiator overheats - the steam under pressure is pushed past the radiator cap - and when it exits, is forced through a "whistle" located on the lower side of the engine.

Looks something like this :

Part 180 goes into part 260

 

[Lzybmbjj30]

I've never heard anything make a steaming, screeching or whistling noise when it happens. The only thing I remember was one time on a hot day last summer the water in the radiator started boiling over but it hasn't done that since I put coolant in but remember I never flushed the system before I did that.

 

[85Hokie]

I've never heard anything make a steaming or screeching noise when it happens.

Look at post 13 - anything here we need to know?
Any and everything helps

 

[Delmar]

Not to go off in the weeds, but there is a horn. I know because I discovered it by accident while working on my old G1900. It's under the seat. No reference in owner's manual, but it's there and it's LOUD! I almost swallowed my tongue when I shorted a temp gauge wire and it went off.

 

[Lzybmbjj30]

What is being used on the PTO? your MMM? are you sure the belt is correct and not binding anything? All the spindles greased well?

Loading the PTO works the engine pretty good - most of the time, you'll find a lot of problems more quickly when placing the load on the engine for a bit of time - overheating is just one that can be found quicker working the engine.

If you go up the hill - PTO not engaged - no problems pulling the hill? You going up hill in Low or High gear(s)

There still seems to be too many intangibles to deal with, need to narrow those that do not have any bearing on the situation!

Yes there is an MMM that the pto is hooked to. I haven't greased anything on it since I've gotten it from the previous owner in 2014. I did check the pulleys on the MMM and the belt looks fine. I'm able to rotate them by hand pretty easily and they don't feel stuck.

I remember that recently when mowing the blade would leave thin strips of grass un cut occasionally. I also notice it tends to shut off a lot when the blade is set low but the grass really isn't that tall.
Without the PTO engaged I've never had a problem on hills up or down.

 

[Lzybmbjj30]

Before I move any further I want to make sure the cooling system gets flushed and new coolant in the engine. There are 2 drain cocks on my engine. There is one under the radiator and another one on the engine block. The one on the radiator drains fine. When I open the one on the block it's bone dry and I have no idea why. Even when I fill the radiator with water nothing comes out of it. I want to make sure I can flush both the block and the radiator before putting any coolant in. I've tried poking up inside the drain cock on the block with a tiny screw driver but nothing happens. I'm thinking the drain cock is plugged up with something. I have heard that stop leak can clog those drains. I never used anything like that but the previous owner might have.

I know there is coolant in the block because when I replaced the head gasket there was coolant in the little holes.

Is this going to be a matter of digging out whatever is in the drain cock plugging it or is it more a matter of putting something in the radiator to clean out the whole system?