Can I get an explanation on this CDL Test question?

The answer is "D". they're asking for the most logical answer. not necessarily the correct one. don't focus on the other ones, pick the one that makes the most sense and shows you have "general knowledge" (which is the test I presume this question is off of) about your truck.

edit: shame on me for not reading completely. i missed the "EXCEPT" part and got caught up in the choices rather than reading the question.

 

The biggest and most important word is "except". This is their way of wording things to mess ya up.

 

This is on a test? really?

ok... A is wrong because antifreeze mixed properly is a heat transfer fluid with corrosion inhibitor. Mixed 50/ 50 with water it will carry away more heat than just water and the chemicals keep your engine from rusting from the inside out and it raises the boiling point of the total fluid along with lowering the freeze point.

B Is wrong because the cap provides mechanical pressure that also raises the boiling point of the fluid. I believe the ratio is 1 lb = 4 degrees boiling so if you remove the cap when hot , you remove pressure an potentially start the fluid boiling....

C is correct
D Is a different story........it depends......if the engine is overheating from hard work like pulling Donner or Grapevine then no...do not shut it off if overheating.....it will get hotter before it cools. Pull over and remove the load from the engine. Keep the fan and pump turning to move the fluid and cool it off....even helps to turn on cab heater if you can stand it.

But if it's overheating due to a mechanical failure like a belt etc then yes, turn it off. Running it will only make it worse.

So A is correct on your test?........ Can't say driver, we all run antifreeze here in the south year round so.....I dunno.....

 

A is not correct because antifreeze can be used year round it is not restricted to winter

 

B is true. Not practical but true. The procedure is to protect ones self and cover the radiator cap and loosen to the first notch until the pressure is relieved, then loosen the cap all the way and fill with anti-freeze/coolant. Higher pressures mean higher temps. . This allows faster cooling and proper replacement of coolant

A is false because anti-freeze is also a coolant. (Ethylene glycol)

 

Let me guess? You got that question from a website that makes up questions?

You have to be careful from where you study as questions like this has nothing to do with the test and the person is not qualified as an educator.

B is about the only one that's 100%.

 

"A" has nothing to do with engine overheating as I read it. Antifreeze and coolant are synonymous terms as it's used year round.

"B" is one that you need to be very careful with from a personal safety issue. A truck I had several years ago had back pressure and used coolant like nothing I've ever had. But in order to fill it with coolant, I had to take off the cap. And when I did, it exploded like a geyser EVERY time. But releasing the cap CAREFULLY can allow heat to escape.

"C" is definitely true. If you don't have coolant, the engine will seize up. Not good!

"D" is a Catch-22. If you have lost all your coolant, that engine will seize up and it's pretty much over and done in terms of any life. But if you turn your engine off while it's still red boiling hot, you're in a fix as the high heat can bind everything together. One solution I've done is to turn the heater all the way up to help release some heat and help the temperature go down. It's worked in my car more than once and I've done it in a big truck too.

My thoughts? Go with "A" as your answer.

Other posters correcting me where I could be wrong are MOST appreciated here! I just know that a high engine temperature could be indicative of a problem. But that "A" just makes no sense here as we have to have coolant in the radiator period, and it doesn't matter what you call it either.

 

Get the rest of the questions right and forget this question....