Low Coolant Alert

[michaeldterry]

Utilizing the replies to this thread, Vita and I went to the bus yesterday determined to get to the bottom of the "Low Coolant Alert" and check engine/stop engine lights. The very first thing we did was locate the sight glass and check it visually. No coolant was visible in the sight glass! We fashioned a make shift "dip stick" and lowered it into the surge tank just to see if there was any coolant at all in the tank. There was a small amount at the bottom of the tank, but it was obviously almost dry. We pulled the Prevost Maintenance Manual in the bus and read up on what we needed to buy to fill the cooling system. Luckily, there was an O'Reilly Auto Parts store right up the street. We went and bought a case (6 gallons) of PEAK Long Life 50/50 Prediluted Antifreeze & Coolant and a funnel. Back to the bus and began refilling the surge tank. It took about 4 1/2 gallons! The good news is that the bus started right up, no alerts - no check engine/stop engine lights!

Lesson learned - I must do a much better and more thorough job of my pre-trip inspections consistently! I've been guilty of giving the pre-trip routine a "lick and a promise" more often than not, just checking what happens to be on my mind at the moment.

I need to construct an organized pre-trip checklist for my bus immediately and commit to using it consistently! If anyone has such a checklist that they are willing to share to get me started, it would be most appreciated!

[garyde]

Hi Michael. there are check lists out there. FMCA offeres one every so often. Each Converter usually has a check list in their manual. One of the things I do is to begin my check list early by several days at least so there are no surprises the day I want to be on the road. I still get surprised sometimes.

[truk4u]

Michael,

Sorry I missed you yesterday, I stopped by about noon and no one was around. Thought I would try to give you hand, but you got it all worked out, so your good to go.

[phorner]

Looks like your low coolant sensor is working and performed its job as designed. If it were mine I would make it my immediate mission to figure out where that coolant went..... and why!

[Mark3101]

Did you ever check your oil as suggested to see if that is where the coolant may have wound up? We had that problem at times with trucks...no leak evident, but losing anti-freeze. Usually it was either a bad head gasket that either let it burn up in the combustion process or a water pump that would leak into the pan (all Caterpillar products mind you). If you can't find an external leak, there is usually something more serious wrong.

[Jon Wehrenberg]

I agree with Mark and suggest being very vigilant regarding coolant loss. If no more is lost it is probable there is not a problem, but if coolant needs to be added often, pray that it is leaking out of a hose because cracked heads, bad head gaskets and other mechanical issues mean some serious money will be spent.

Tips I have learned about coolant. The tank with the sight glass is for expansion. If coolant needs to be added bring the coolant level when cold up to and slightly above the sight glass. If it is filled to the top a lot of coolant will be pushed out when the engine comes up to operating temperature.

Adding 4.5 gallons got my attention. Even if the tank is now filled to capacity I doubt if it holds 4.5 gallons so the coolant level was down quite a bit. Refer back to my first paragraph.

As to coolant type, I hope the correct coolant meeting the applicable Detroit spec has been added. I have yet to see coolant available in automotive stores that meets the spec and to avoid any risk of using the wrong coolant have used the Detroit Diesel products or something available at a truck stop with the Detroit spec. The wrong coolant can lead to plugged radiators or failed cylinder liners. I think the 8V92 is more susceptible to these problems than the Series 60.

[flyu2there]

I don't know what the capacity is from the bottom of the sensor to the bottom of the expansion tank however it is obvious that an amount of coolant equal to that value was lost between the times that you ran the bus. That being said, the coolant went somewhere an apparently it was not onto the ground; even a cup full or so will eventually make it to the floor below the engine. Also there has been lots of discussion about organics and inorganics (coolants) on this forum and one has to be careful not to mix the two less you could end up with Jello in your radiator. As Jon mentioned, the anti freeze should meet the DD Spec which will be posted clearly on the container. I am also in agreement that 4.5 gallons of fluid is a big loss, I would investigate a bit further.

[michaeldterry]

Did you ever check your oil as suggested to see if that is where the coolant may have wound up? We had that problem at times with trucks...no leak evident, but losing anti-freeze. Usually it was either a bad head gasket that either let it burn up in the combustion process or a water pump that would leak into the pan (all Caterpillar products mind you). If you can't find an external leak, there is usually something more serious wrong.

Mark - I did pull the dipstick and it seemed to be registering at an acceptable level. However, beyond looking at the level that the oil reaches on the stick, I'm not certain what else I should look for there to see if coolant has leaked into the oil. How would I know? What would I see? Regardless, i'll be monitoring coolant and oil levels extra closely in the days and weeks to come!

[michaeldterry]

Michael,

Sorry I missed you yesterday, I stopped by about noon and no one was around. Thought I would try to give you hand, but you got it all worked out, so your good to go.

Tom - I'm sorry we missed you, too! We had family Easter obligations at Vita's parents house and had to take an extended mid-day break from our bus adventures to put in the requisite appearance over there! If you would have called my or Vita's cell though, we would have dropped everything and come running!

[Mark3101]

Mark - I did pull the dipstick and it seemed to be registering at an acceptable level. However, beyond looking at the level that the oil reaches on the stick, I'm not certain what else I should look for there to see if coolant has leaked into the oil. How would I know? What would I see? Regardless, i'll be monitoring coolant and oil levels extra closely in the days and weeks to come!

Normally, the oil would turn milky in color if there was anti-freeze in it. That was a dead giveaway that something was amiss. Since you put over 4 gallons of coolant in, if it had gone in the oil pan it would be way over full unless you were 4+ gallons low on oil. If I were you, and you are sure there is no external leak, I would take it to a shop and have the cooling system pressure tested to see if the leak can be found. It would be fairly cheap to do and is not too time consuming either. The peace of mind knowing where the coolant went would be worth it I think.....

Also, Jon's thought about having the right type of anti-freeze in the system is also something worth checking. Mixing the wrong type can be bad news as he stated. You could find that out from the tech while getting the system pressure tested if you are not sure yourself from the info on the package. Depending on if a leak is found, you may have to dump all the coolant to fix it and that would be an ideal time to get it right if it is not.