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woodlanda
01-22-2013, 11:16 PM
Bought a used 2008 bobcat 463 with 940 hours,
it has a Diesel kubota engine
-previous owner had replaced the radiator

its my first bobcat so not to sure whats going on

-used it three separate times for about 2 hours each time in temps ranging from -10 to -15 C weather , no issues

i went to use it again, had it running for about 30 minutes clearing snow and noticed the temp gauge was in the orange, (outside temp -12 c) immediately went to park it off the street and i throttled it down gauge instantly jumped to low green again... when i rev ed it up to move it to the garage the gauge jumped instantly again to orange.

-checked the coolant levels and they are full, checked the air filters, they seem pretty clean,the radiator is clean and no debris, oil level is good, fans are working, can feel the air flow going through the rad

the next day my dad and i started it up, just idling and within about 5 minutes the gauge went up and was reading orange and remained orange, we had an infrared thermometer to check the temp of the coolant hoses and cylinder heads, the temperatures seemed to be running at around 180 f, we disconnected the fans to see make sure they were, the engine temp would rise a bit and when we reconnected them the temp would go down based on the infrared thermometer, the gauge in the cab is however reading orange/ overheating, Not sure what is causing the problem, or if it is actually overheating

we checked for air in the coolant and no bubbles coming up in the funnel

had the machine idling and ran at full throttle for close to 20 minutes and the infrared thermometer temps remained around 180 f
when we went from full throttle to idle the temp cab gauge didn't go down

the outside air temp was -10 c

Ive been reading online and not sure if it has a cracked cylinder head, bad thermostat, bad sender or gauge, water pump?

anyone know of or have had experience with similar problems and know how to fix or troubleshoot the problem or to determine if in it is actually overheating or just a gauge issue or
WORSE CASE scenario: what are the symptoms for a cracked cylinder head without pulling the engine apart? I hope it isn't!!

any help suggestions would be appreciated

Landrus2
01-22-2013, 11:44 PM
Replace radiator cap :waving:

teckjohn
01-23-2013, 09:22 AM
If its hot and the jumps to green sounds like it was stuck and then opened.

woodlanda
01-30-2013, 12:32 AM
Fixed temp gauge problem

Changed the radiator cap to a 13 psi originally had a 15 psi cap, changed the thermostat as well as the sensor for the temp gauge, seems to have fixed the problem

- I replaced coolant and noticing a steady stream of bubbles coming into the overflow container from radiator, not sure if it is air in system

I'm going to run the the machine and keep an eye on coolant levels

teckjohn
01-30-2013, 08:51 AM
Cool Glad ya got it. why did you change to a lower pressure cap?

piston slapper
01-30-2013, 09:00 PM
By changing the thermostat...sender..and a lower pressure cap...at the same time...it is impossible to nail down the exact cause or causes of your temp issues...however...it looks like you made the right call...
The lower pressure cap will allow the coolant to be diverted to the reservior at a lower temperarure...lowering engine temps..

ecurbthims
01-30-2013, 09:29 PM
I think the only thing wrong was the temp sender ,as there is nothing overheating at 180 degrees ,if anything thats running on the cold side .

Landrus2
01-30-2013, 09:56 PM
Quote:
Originally Posted by TheKirbyMan
What would happen if you ran a cap with too low of a rating?
A 50/50 mixture of antifreeze and water boils at 227 deg F at atmospheric pressure. As you increase the pressure, you increase the boiling point. The pressure vs boiling point looks like this:

0 psi 227 F
4 psi 236 F
8 pis 248 F
12 psi 259 F
16 psi 267 F

So, if you run a lower pressure cap, you coolant will boil at a lower temperature. About the only time you would notice this is when your engine overheated for some reason, or when you shut the engine off and the coolant in the engine block heated up.

I have always run 7 psi caps on most of my cars, including cars with 205 degree thermostats. But, I am willing to live with the possible consequences. For example, if for some reason my engine overheats, it is going to blow off coolant. I keep several gallons of water/antifreeze in my car at all times. I also make sure my overflow line to the overflow tank is in good condition and is not leaking. When I shut the engine off on a really hot day, sometimes some coolant will belch into the overflow tank. When the engine cools, it draws it back into the radiator again. It will only do this if the entire cooling system, including the overflow hose, is well sealed.

The strain on hoses and water pump seals is a lot lower at 7 psi. Since switching to 7 psi caps (20 years ago) I have never had a hose blow out on me or a water pump shaft seal leak.

If you run a lower pressure cap, be prepared for the occasional emergency.:waving:

piston slapper
01-31-2013, 09:44 AM
Thank you...TheKirbyMan........ for some really good info on radiator caps..
You can never get too much good information..

Landrus2
01-31-2013, 06:32 PM
Thank you...TheKirbyMan........ for some really good info on radiator caps..
You can never get too much good information..

Yes we all can learn from him:waving:

piston slapper
01-31-2013, 06:59 PM
Well ....perhaps those that didn't learn that stuff in basic automotive repair manuals...

My hat is off to RestroRob...Dutch1...BigFish..Ed2Hess..Ricky86...and all the other Factory Trained Technicians like myself...that take time out of their busy schedules...to help people they don't even know...
It ain't bragging...if you can do it....

Landrus2
01-31-2013, 07:53 PM
Well ....perhaps those that didn't learn that stuff in basic automotive repair manuals...

My hat is off to RestroRob...Dutch1...BigFish..Ed2Hess..Ricky86...and all the other Factory Trained Technicians like myself...that take time out of their busy schedules...to help people they don't even know...
It ain't bragging...if you can do it....

Yes I do admire and respect they work. We all can learn from them:waving:

piston slapper
01-31-2013, 08:36 PM
Yes I do admire and respect they work. We all can learn from them:waving:

Perhaps....I can see you are jazzed about this forum...a regular rah rah cheerleader...
As. I was never priveliged to receive a pm from you...and there is really no background info on your member page..
I guess I will ask you in open forum....
What is your mechanical background.?..and what special qualities do you bring to this forum.?
Enquiring minds want to know...

Landrus2
01-31-2013, 08:52 PM
Perhaps....I can see you are jazzed about this forum...a regular rah rah cheerleader...
As. I was never priveliged to receive a pm from you...and there is really no background info on your member page..
I guess I will ask you in open forum....
What is your mechanical background.?..and what special qualities do you bring to this forum.?
Enquiring minds want to know...

I have no problem telling you we do our maintenance since 1979 on our equipment. OK small engines Kawasaki ,kohler,Briggs,Wisconsin ,Honda ,
We have some Kawasaki's with 3200 hours is that good service or what.
We leave the big engines for tomorrow :waving::waving:

piston slapper
01-31-2013, 09:12 PM
Not to split hairs here...but I was not referring to "WE"....I was asking about "YOU"
I'm sure we would ALL like to know more about the guy that has an opinion on everything..
It can be very distracting when trying to have an intelligent conversation to have people jump in the middle without adding anything to the solution...
Offering good technical advice with limited information is already pretty tough..

Landrus2
01-31-2013, 09:17 PM
Not to split hairs here...but I was not referring to "WE"....I was asking about "YOU"
I'm sure we would ALL like to know more about the guy that has an opinion on everything..
It can be very distracting when trying to have an intelligent conversation to have people jump in the middle without adding anything to the solution...
Offering good technical advice with limited information is already pretty tough..

I was me and my brothers members here to.:waving:

piston slapper
01-31-2013, 09:28 PM
I was me and my brothers members here to.:waving:

I should have known I couldn't get a straight answer ...
This must be the only place where a student can constantly disrupt the class...
And nothing is done about it...

woodlanda
03-14-2013, 01:48 AM
I guess it isn't fixed as the Bobcat 463 was acting up again and kept telling me it was overheating. There was still bubbles popping up in the overflow coolant container when the engine ran. I got one of those glass test tube kits that you place in the radiator cap and if there is color change in the test tube it indicates that you you have a crack in the block head or gasket. The test confirmed a problem. It took about 4.5 hours to get the engine apart and the block head removed. It turned out there was a small crack in the block head leading from one of the pistons to the coolant chamber. I got a new block head on order from Bobcat and hopefully it will fix the problem.