Diesel

[John]

Hello Eric. Enjoy your videos, I was hoping if you could do a video about diesels. I wish to invest in car or small SUV for better fuel economy, but I’m not sure what to look for when looking used, and what would need to be done to get in good shape (tune up). Any advice would help

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[EricTheCarGuy]

Before I purchased the Fairmont I was looking for a diesel vehicle to use in my videos. I ended up with the Fairmont instead. That said, I do hope to get one some day to use in future videos. To be honest there’s a thing or 2 that I could learn about them myself.

Thanks for the suggestion.

[James O’Hara]

I am a diesel mechanic and I own a 2005.5 1.9L TDI Jetta Sedan Manual. What ever you do do not buy my model year or any transitional year when they are switching to a new model. What sort of things are you looking to know. If you buy used regardless of the fact that most diesels will run for a long time buy one with as low mileage as you can afford. You have to remember that while the engine is meant to run for a long time the rest of the vehicle is built like the gas equivalent. So therefore the length of suspension parts, tires, transmissions, etc, etc is likely to good bad during the same time frames. Something that is very important to look for is oil in the charge air line between the turbo and the charge air cooler (Intercooler). This indicates a previously failed or currently failing turbo. You want to look for proper oil and fuel filter changes. Diesels have to be serviced on time within 100-200 miles of the service interval. With diesel engines there is soot that gets into the oil it is a byproduct of the diesel fuel. This is why even brand new oil looks black so to check you need to smear a drop on a piece of paper and check for the darkness/specs of soot. If oil changes were not done religiously within that 100-200 miles of the service interval it will cause excessive wear on all the internals. Diesel engines also require the fuel filters to be changed more often. Make sure they were done during the proper times. If they have not been since almost all modern diesel engines are direct injection it can clog injectors. The problem with this is it causes the valves to get burnt and injector damage due to the much higher temperatures and compression ratios that diesels run and it can also cause a cylinder head to warp. Another thing that you want to make sure of is that you don’t have what looks like a gray/choc milkshake in your oil dipstick this indicates a leaking EGR (Exhaust Gas Recirculation) or oil cooler. This occurs more frequently on diesels due to normally an increase in oil pressure. You also want to check the intake for carbon buildup and that the EGR is functional. If it is not it will not pass emissions which some states do have for diesels now. Also make sure to find out when the transmission fluid was last checked and if it is an automatic when the last time it was rebuilt especially with significant mileage on it. If it is a sealed transmission ask them to do a flush if it is a manual. Transmissions consume oil over time and sealed units are rarely checked. If a manual flywheel and clutch if it has an inspection cover it is easy to burn them up if the clutch was not kept properly adjusted. Also check the parking brake. With a diesel engine and the low end torque it easy to go a long way with the parking break on and not notice this will eat up the parking breaks and depending on the style the rotor/drum. If it has higher mileage check all fluids to make sure they have been changed. Also due to the weight of the engine is higher then most and some manufacturers do not account for this check for the suspension being out of shape.

And that is about everything I can think of. I also suggest you get the valves adjusted after purchase because there is very low clearance in diesel engines thing thousands of an inch. Plus in diesels they normally go out of spec between 60k-120k miles and it makes a bigger difference in performance in a diesel then in a gas engine.

If you are looking for a truck I would suggest getting one with a cummins engine and an allison transmission (if you can find one). Allisons are normally automatics but, are pretty much bulletproof and cummins engines are the same. Though both have to be taken care of properly with service intervals followed. If you are looking for a car I would stay away from VW, Audi, Mercedes. Diesel parts are more expensive to begin with then adding the fact they are made in germany just adds to the cost unless you are in Europe then I would go for it.

[Author]

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