Over Weight and Over Heating

Vehicle weight is a major issue that many Four Wheel Drive owners are often unaware of or just ignore. This is not only a performance issue but also a safety issue and not just for the vehicle owner but also for other road users. At Berrima Diesel Service ( www.berrimadiesel.com.au ) they usually see half a dozen 4WDs in their workshop every day for tuning, performance problems or turbo charging. During the process of their work they weigh the vehicles as part of the job. They do this as they have most vehicles coming in for a power gain. It might end up with the power gain at the wheels, but it may not push the vehicle as thought. This is where the weighing process comes in, sometimes with surprising results. They utilize a modern electronic weighbridge that is accurate to within 10kg.

Considering that the average 4WD truck only has a payload capacity of just over half a tonne, it doesn't take long to swallow that up with 2 or 4 occupants, oils in the engine, diffs, gearbox, fuel in the tank/s, the normal accessories like bull bar, tow-bar, heavier suspension (big springs and shocks are literally heavier). Even different tires can weigh substantially more than standard .Generally, the big wagons have a maximum GVM (max loaded weight) of 2.9 tonne to 3.1 tonne. Berrima Diesel see the average ones weighing 2.9 tonne to 3 tonnes and they are certainly not loaded for a trip. When they get the accessorized big wagons in they start to reach towards 3.2 tonnes and they have seen the odd 100 series Landcruiser in their workshop, obviously with a lack of power problem, weighing in at 3.5 tonnes. When you talk Troopers, they regularly weigh over their GVM as they are stacked up with all the heavy gear needed for the trip. Large steel fuel tanks not only carry a lot more fuel (weight) but weigh in surprisingly more than the factory poly or tin tank. One recent GU Patrol went over 3 tonne and the vehicle wasn't what you would call heavily modified, just the usual 'steel gear'.

A big problem arising from the ever increasing weight of 4WD's is fuel consumption. A standard 4WD diesel can start off with a happy consumption figure of around 10-12 liters/100km only to have it blow out to 16ltres/100km once modified.

Tyre blowouts are common on a lot of trips and this is an area that weight can have a huge effect. Standard tires are designed to work within the working parameters of the vehicle but once it is over weighted the standard tires are often working very close to their maximum weight limit. Throw in an extremely hot road and the working weight of the tire gets lower. When considering loading up next time, check the loaded weight of the vehicle and check the combined load rating of the tires. Make sure you have a good percentage of difference between the tires and the weight of the 4WD they are carrying. Eg. probably 20% to 30% less weight of the vehicle than the maximum tire carrying load.
Wheel bearings are another thing to consider. Make sure that they are greased if you are carrying weight.

Overweight vehicles are the main reason for performance problems. Not only that but they are often illegally overweight. Ask the people how much they think their 4WD weighs and the general answer is 2.2 tonne or 2.4 tonne. When Berrima Diesel explain that it weighs in at 3 tonne or more they have trouble believing it!! Add to this the 2 tonne trailer and you have, for example, a 3 liter Nissan trying to move a combined weight of 4.5 to 5 tonnes!!

Overweight vehicles can also become an insurance issue in the case of an accident. A listed weight, initiated by the accessory manufacturer on accessories, would be of a great benefit to people.

Some other areas to consider that can effect vehicle weight areas steel refrigerators, larger tires, upgraded suspension also lends itself to more weight as well as thicker springs, storage drawers, roof racks, dual batteries, different seats, HF radios. People usually need these for trips but at least an awareness of where the weight is coming from can help with controlling it.

Find a reputable weigh bridge or just turn into an RTA truck weigh bridge for free and get ready for a possible shock!

Radiators and Air flow:

*    Consider a larger radiator. Some Factory radiators are a 2 core and can be increased to a 3 core radiator.
*    Please… resist fly screens where possible.
*    Consider the size and positioning of driving lights, winch, number plates and particularly bull bar air flow.
*    Check to make sure air conditioning condenser fins are clean!!
*    If an Inter-cooler is mounted in front this can add considerably to hot air flow over the radiator and restricting air flow to the radiator.
*    Consider installing a few small bonnet vents on the left and right of the rear region of the bonnet. This has proven to be a popular addition and has huge effects on under bonnet temperatures. Considering how tight most engine bays are after a few accessories are added, this venting addition can reduce heat stress on a variety of products under the bonnet.

Engine set-up:

*    Over fueling is usually the major cause of high combustion temperatures.
*    Make sure the fuel injection system has been thoroughly checked and setup correctly.
*    If the vehicle is fitted with a turbo or super charger, over fueling may be the cause. It is very easy to over fuel a diesel once plenty of air is available as possibly no smoke under load may be visible. Visible smoke under load can be a warning of over fueling!

This article and the technical advice was taken from an interview with Andrew Leimroth of Berrima Diesel Service. Andrew is one of The Diesel Experts who have been working exclusively on diesels since 1965. His wealth of knowledge and skill with problem diesels is well known in the automotive industry.
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Auto Repair: The Top Ten Mistakes Made By Your Mechanic

Number One:

Not confirming the concern. Confirming a repair concern is a basic diagnostic principle frequently overlooked. To fix a problem, the first thing one must do is recognize it.

Number Two:
Insufficient Road Testing. The importance of a thorough road test (even for an oil change) is well documented in automotive training manuals. Yet, many technicians consider driving the vehicle into the shop good enough.

Number Three:
Misdiagnosing. For the above reasons and a multitude of others, your vehicle is misdiagnosed more often than not. Mechanics will spend hours chasing the wrong problem, wasting your time and money.

Number Four:
Throwing parts at a problem. To compensate for lack of skills, mechanics often just throw parts at the problem in the hope of getting lucky. It’s common to hear mechanics say I replaced this, this, this, and that, and the problem’s still not fixed. This goes right back to mistake number one: confirm the problem with diagnostics, then proceed.

Number Five:
Not addressing primary concerns first. Technicians often spend an inordinate amount of time looking for easy sells that will fatten their paychecks. There’s nothing wrong with this provided there’s no charge for the inspection, it doesn’t conflict with your time, and the upsell suggestions are valid (they’re frequently not). However, this type of free inspection and the subsequent upselling too often overshadows the primary concern. So…what’s wrong with my car?

Number Six:
Overconfidence. Too often unqualified technicians get in over their heads. Rather than defer to a more experienced technician or facility, they often keep going and do more harm. How’s it go…The road to hell is paved with good intentions?

Number Seven:
Taking shortcuts. In the ongoing effort to beat the clock, technicians will create a host of problems: breaking parts, snapping bolts, short circuiting sensitive electronics. Refer to Auto Repair: How Can They Screw Up an Oil Change for a great discussion.

Number Eight:
Poor Repairs. Whether through incompetence or laziness, mechanics frequently don’t do repairs correctly. It’s often sloppy work. Forgotten bolts, parts not lined up correctly, or components not re-installed properly are common. It gets worse with computer repairs: incorrect software programming, coding, and resynchronization protocols are just a few.

Number Nine:
Not confirming repairs. After a repair is complete, it’s important to re-check to ensure that the problem is indeed fixed. Too often parts are thrown in and the car is pulled out only to pull in another victim.

Number Ten:
Making a mess. If the above nine mistakes weren’t bad enough, there are now greasy fingerprints on the hood and steering wheel, and two big greasy boot marks on the carpet.

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