How To Tell If Your Engine Block Is Cracked

The coolant in your Mitsubishi Fuso, Isuzu, Hino, or UD freight truck operates in a closed system, meaning that it circulates from the engine’s cooling passages to the radiator, the heater core and back again. It should never leave that loop. If somehow getting into the oil passages or the cylinders (and, from there, out the tailpipe) something has gone terribly wrong. Your head gasket has cracked, your head itself has cracked or, worst of all, your block has cracked.

You can crack an engine block many different ways, but some of the more common ways are:

– Running water through the cooling system instead of antifreeze in cold weather
– Running cold water through an already hot engine

A cracked engine block can cause performance troubles with any Mitsubishi Fuso FE, FH, FK or UD 1200, 1300, 1400, 1800 or 2000 series, Isuzu NPR, NQR, GMC W3500, 4500, 5500, any other mid size truck or even regular passenger cars, and in time, can cause your vehicle to stop running altogether. Fortunately, there are ways to identify a crack in the engine block, which can help lead to repairs or replacements.

  1. Look for leaking engine coolant, most notably as it drains out the bottom of a car. This is a telltale sign of a cracked engine block, and in time, can cause an engine to overheat.
  2. Check the dashboard and check gauges. If any of the dashboard lights come on, whether related to oil or coolant, this could signify a cracked engine block. Also, if the temperature gauge begins to signal overheating, this could mean engine coolant is leaking, which is a potential sign of a cracked engine block.
  3. Look for extra smoke coming out of an automobile’s exhaust pipe. While a certain amount is common, extra amounts–long trails coming out of an exhaust pipe–could signify a cracked engine block.
  4. Check to see if a car radiator’s mixture of engine coolant and water is optimal. This should be half water, half antifreeze, in most cases (it will often be indicated on an antifreeze bottle’s instructions). If the mixture is not proper, this can cause the mixture to freeze, which will crack the engine block.

There are very few engine failures that any mechanic would consider beyond repair, but first among them is the cracked engine block. The end result is generally irreparable damage. Additives like sodium silicate (a.k.a. “liquid glass”) can help delay complete failure of a slightly fractured block, but it will never be as strong or reliable as it once was.

Engine Block Cracked?

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New NPR and NQR Transmission Fluid Requirements

From late 2007 and up, NQR and NPR Imported Trucks come with a new type of automatic transmission that requires an inexpensive silicone-based transmission fluid.

It is a must that you use a silicone-based fluid such as Isuzu SCS Automatic Transmission Fluid — Isuzu part # 2-90531-200-0.  If you don’t use the proper fluid, it will burn up your transmission in a matter of a day.  You cannot use regular automatic transmission fluid or a petroleum based fluid in the NQR or NPR trucks built after late 2007.  This fluid is not expensive at all, it costs about the same as Dexron.

We have already seen what using the wrong fluid will do to the transmission. We have had several transmissions that were burnt-up under warranty because they had used regular Dexron/Mercon fluid.

Which models require the new fluid?

Isuzu started producing this transmisison in mid-2007, some ’07 models use the fluid and some don’t.  Anything later than ’07 will require the new transmission fluid and late model 2007 trucks will require the new transmission fluid as well.

How to Identify Your 2007 Model NPR or NQR

Late model 2007 trucks will require the new silicone-based fluid such as Isuzu SCS Automatic Transmission Fluid — Isuzu part # 2-90531-200-0.  If you have a 2007 model Isuzu NPR or NQR, you can easily identify if you have the old style ’07 or the new style ’07, by the door handle.  It’s that easy.

If you have the new style – a late ’07 (bottom photo) – you need to use the silicone-based fluid such as Isuzu SCS Automatic Transmission Fluid — Isuzu part # 2-90531-200-0.  It is very important not to mix the fluids, know which one you need.

Fluid Requirements on Dip Stick

Also, you can identify what fluid you need by looking at the top of the disptick tube located on the driver’s side of the truck aftery oyou’ve flipped the cab forward .

The dispstick tube will be located right where the motor and transmission bolt together just behind where the starter bolts to the transmission. At the top of that tube, the small print will tell you what kind of fluid your truck requires, an SCS fluid or an ATM fluid.  The SCS is the new silicone-based one.

We realize that the trucks that we sell parts for are critical for your business. We want to do everything we can to help you succeed and to keep your Isuzu NPR box trucks, Mitsubishi Fuso, Hino and UD mid-range box trucks, Chevy W3500, W4500, W5500 trucks and any other vehicles in your fleet running.


Don’t Trust the Jug – Prevent Engine Failure

Don’t trust the jug, jug being the radiator reservoir jug. I’ve seen this problem a lot. Your car or truck seems to be running hot, but you have plenty of coolant in your radiator reservoir jug, so you think it’s fine. But it’s not and your engine gets ruined.

This is especially serious on your Isuzu npr, Isuzu nqr, Isuzu ftr and frrs, the UD1200, UD1300, UD1400, UD1800, UD2600 trucks because they are much more expensive than cars.

What happens is, in a vacuum reservoir type system, the engine gets a leak or the hose gets a leak . This system counts on a vacuum to draw water out, which is fine until you get a hole in the cooling system somewhere. Then it can’t draw water out — can’t pull a vacuum; therefore, your truck runs hot. This ruins a very expensive motor and causes thousands of dollars in damage within just a few minutes.
The best way to avoid this problem, is to physically lift the cab before you crank in the morning when the engine has been cool for at least 2-3 hours and physically check the radiator level.

DO NOT OPEN THE RADIATOR UNTIL THE ENGINE HAS AT LEAST SEVERAL HOURS COOLING TIME. Open the radiator, on a cold engine, very slowly. If you open the radiator on a warm or hot engine, you will risk getting seriously burned.
Just because the reservoir jug may be full, does NOT mean you have coolant in the radiator. Please check the coolant in the radiator while the truck is cold.