CAT 3126B Block Warming

[chucknewman]

My CAT 3126B air inlet heater appears to be working OK, though I haven't spent a lot of time in really cold climates. That may change this winter.

I have a diesel furnace that also heats the hot water. Part of the system consists of a heat exchanger that uses engine coolant to heat the hydronic system coolant (and HWH) to warm the entire coach while driving down the road. It works very well without using the furnace. But it won't work in reverse without another electric pump to circulate the engine coolant when the engine is off; warming the block while using the diesel furnace. Is this feasible? Will I need to bypass the new pump when the engine is running? Will the 3126B thermostats affect the flow? Is the direction of flow important?

Or another option:

I see immersion type electric block heaters for sale, supposedly for the 3126B engine, but can't find any installation data. Is there an unused port somewhere on the 3126B block where this of block heater is typically installed?

I lean toward the added pump system since it won't require 120 vac all night to heat the engine. Not always on shore power.

Or is the air inlet heater all I need for temperatures down to and below zero degrees F at high altitudes with thin air?

Chuck

[wolfe10]

Chuck,

Are you sure you don't already have a 120 VAC block heater?

If not, yes, there are aftermarket block heaters that replace a freeze plug on the 3126. Here is one manufacturer: http://www.hotstart.com/home/products/in-block-heaters/

Enter: Caterpillar and then 3126 side.

As far as using your hydronic system to heat the pre-heat the engine, and what would be involved, that is a question for the manufacturer of your hydronic system. and may depend on how your coach's hydronic system is plumbed.

[chucknewman]

Brett,

"Are you sure you don't already have a 120 VAC block heater?" Well, not totally sure. I put one into a Detroit Series 50 engine so I know what the element and power cord look like. I don't see that anywhere on my block. Plus I've never heard of SMC putting them on any of their coaches. I have no dash switch indicating same.

I've studied, diagrammed, and maintained the hydronic system. I know all I need to do to is to pump the engine coolant through the existing heat exchanger when the engine is off. I can install a pump bypass valve to effectively remove the pump from the engine coolant flow when the engine water pump is running.

Brett, with heated engine coolant to about 170 to 180 degrees, I presume the 190 degree CAT thermostats won't fully open. Will that make a difference as far as circulating hot coolant around the engine?

Does the 3126B have a thermostat bypass like most automotive engines?

Chuck

[wolfe10]

Chuck,

Yes block heater/no block heater is a decision made by the chassis/coach maker. But, if no 120 VAC "extension cord" coming from the block (normal location on the 3126 is on the driver's side below the turbo) Safari may not have installed or speced one. It would plug into a 120 VAC outlet-- likely in the engine compartment.

When the thermostats(s) (later 3126's have two thermostats) are closed, there is a bypass back to the engine, not to the radiator. Shouldn't be an issue with temperatures below that of the opening temperature of the thermostat.

But, you will be wasting a LOT of power bring the engine up to full operating temperature with any auxiliary heater. Even with that kind of temperature available, consider just turning it on for a time before starting the engine, but not long enough for the engine coolant temperature to fully reach operating temperature.

Brett

[chucknewman]

Thank you Brett for the information. That helps me make the decision to use the already installed infrastructure. Using the same model new pump will cost about twice as much as the immersion heater, but much easier to install. And it eliminates the separate power issue.

Chuck

[daviddon]

Hi,

I found you all in the process of researching a block heater for a Cat 3126.

There is a rear THREADED plug on that engine. HotStart has an expense heater that fits that plug and probably others have heaters. Search for "TL101-000" and you can find an installation sheet. Surely a threaded bushing could be inserted into the original plug female fitting and other generic and cheaper heaters could be installed.

Of all the solutions, this strikes me as being the safest and most fool proof. It should eliminate chances of coolant leakage and fire. I would much prefer to plug this heating element and forget it than fret over other methods. Removing a freeze plug in an installed engine might be a recipe for leakage.

[wolfe10]

My Caterpillar 3116 (the predecessor to the 3126) came with a Caterpillar block heater. It is located in the water jacket/side of block just below the turbo. The element went out, so I just replaced it. Note, this is one of the two locations for a block heater on the 3126, per Hotstart's website.

Here is the process:

I got a Hotstart FP101-001 http://www.hotstart.com/home/products/in-block-heaters/. It replaces the freeze plug/old block heater. They recommended Loctite 640 as a sealant. Took a little research to find the Loctite 640.

Drain coolant. Mine was still in good shape (Caterpillar ELC), so I was careful to catch it and keep it clean. Replaced the coolant filter (zero unit SCA filter, as my coolant is ELC which does not use SCA).

Remove old block heater. Dry that area of the block (paper towels)

Clean block wall/opening with 400 grit wet dry sandpaper so the new block heater and Loctite would have a good clean mounting surface.

With a socket as a driver, used a hammer to drive the new block heater into place (didn't require any heavy pounding-- just make sure it is square).

Let Loctite set up overnight (set up time depends on ambient temperature-- complete information on their website: http://www.all-spec.com/downloads/loctite/64031_120209s.pdf

Refill cooling system. On most cooling systems, you must "burp" the air from the engine thermostat housing. Some have a chassis manufacturer run line that does this automatically. On mine, I just loosen the coolant line from the thermostat housing to the air compressor until coolant starts coming out.

Put on a Willie Nelson CD and sing along with... "Back On The Road Again".

Brett

[chucknewman]

Brett, a couple questions re the above post:

"Replaced the coolant filter (zero unit SCA filter, as my coolant is ELC which does not use SCA)." I know ELC does not require SCA testing, but did you have a "non-sca" (as in plain) water or coolant filter on your 3116? If so, should I expect to have one (inline or screw on) or is it something the coach manufacturer would have added. Please elaborate? Also, would you recommend a non-sca coolant filter in the system?

Regarding "...you must "burp" the air from the engine thermostat housing." While watching the CAT tech replace the thermostats several months ago I asked him about burping the cooling system. I don't remember his exact words other than he did say that was not necessary on my system. Is it due to the fact that my coolant poly overflow tank runs at coolant system pressure and bleeds out air via the pressure cap (12 psi) vent line to the ground?

Is a pressurized overflow tank typical on larger diesel engines? All the overflow tanks I've seen on cars, pickups, and motor-generators were at atmosphere and not system pressure. Can you enlighten me on this please?

Many thanks,

Chuck

[wolfe10]

Chuck,

My response in red.

Brett

Brett, a couple questions re the above post:

"Replaced the coolant filter (zero unit SCA filter, as my coolant is ELC which does not use SCA)." I know ELC does not require SCA testing, but did you have a "non-sca" (as in plain) water or coolant filter on your 3116? If so, should I expect to have one (inline or screw on) or is it something the coach manufacturer would have added. Please elaborate? Also, would you recommend a non-sca coolant filter in the system?

Foretravel installed a spin on coolant filter remotely mounted off the engine in the return line from engine aid water heater and dash heater. If one uses a coolant that requires added SCA, installing a filter with "units" of SCA is one way to add the SCA (liquid SCA being the other-- same chemical). Said another way, a coolant filter with SCA is both a filter and adds SCA to the coolant as soon as coolant circulation begins. Since ELC does not use SCA, you replace the filter with a zero unit (i.e. no) SCA filter. It serves the same filtration duty, but does not add SCA.

Regarding "...you must "burp" the air from the engine thermostat housing." While watching the CAT tech replace the thermostats several months ago I asked him about burping the cooling system. I don't remember his exact words other than he did say that was not necessary on my system. Is it due to the fact that my coolant poly overflow tank runs at coolant system pressure and bleeds out air via the pressure cap (12 psi) vent line to the ground?

It depends on whether there is a bleed line from thermostat housing. If so, many do run to the overflow tank, though it could run to the top of the radiator. No big deal one way or the other AS LONG AS YOU GET THE AIR OUT OF THE THERMOSTAT HOUSING. Pretty easy to tell if you have an air lock. After replacing the coolant. Start the engine. If the temperature gauge does not start to move (needle off cold peg) within a couple of minutes, you have air in the housing. Better answer is to look at the thermostat housing. If no small hose coming off it, crack open a line such as the cooling line to the on-engine air pump until coolant with no bubbles comes out. Yet another option if you are replacing the thermostats is to change the coolant, leaving the thermostat for last. Fill the last couple of gallons into the thermostat housing until the fluid level is just about to overflow the housing.

Is a pressurized overflow tank typical on larger diesel engines? All the overflow tanks I've seen on cars, pickups, and motor-generators were at atmosphere and not system pressure. Can you enlighten me on this please?

Some are pressurized, others have the pressure on the radiator itself with vented overflow (like a car).

Many thanks,

You are welcome.

Chuck