More Info On VR6 Engine For Sale – Mk4 Volkswagen VW Jetta GLI Golf GTI 24v Vr6 2.8 BDF Complete Engine
VW VR6 Tuning & Common Problems
The Volkswagen VR6 engine is a versatile and powerful engine that VW most notably used in the Audi 5000, Passat, and EuroVan. It has also been used in VW Golfs, VW Jettas, VW Beetles, and VW Sciroccos.
The VR6 offers excellent performance for both stock cars and highly modified ones because of its ability to withstand high horsepower numbers. This article will discuss some common problems with this engine, such as overheating or lack of power.
VR6 Engine Specs
The VR6 is a unique engine with some very distinct features that separate it from other VW engines.
Firstly the VR6 is not one engine but two three-cylinder sub-assemblies put together on the same crankshaft. The two sub-assemblies are offset 90° apart, and each 'part' has its cylinder head, valves, and camshaft.
The advantage of this unusual design is that the engine can utilize a narrow Vee-angle, which decreases friction between moving parts while increasing power output - unfortunately, the increased width/length of the engine offsets some of these benefits. The cylinders are also 'siamese together, meaning they share a water jacket to help the engine stay cool. The exhaust manifolds at the base of each cylinder can also be seen in this image.
Both cylinders on one bank fire simultaneously at idle, and then there is a 4° ignition phase difference between each side/bank, which allows even firing when under load. This results in an idle sound resembling two 3-cylinder engines rather than one 6-cylinder engine.
The VR6 is unique in that it has no camshaft or cams whatsoever - instead, the intake valves are opened via low-pressure oil acting directly on the cam followers; this means there are no pushrods, unlike many conventional Vee engines which have pushrods from the camshaft to rocker arms on top of each valve.
Interestingly, the intake manifold uses a Helmholtz resonator design used initially in German aircraft - this helps increase induction sound and 'louder' the engine.
The other innovation with this engine is that the intake and exhaust manifold has a cooling effect because the exhaust valves are water-cooled. In contrast, many car engines pass water through the inlet manifold.
Common VR6 Engine Problems
VR6 Engine Cooling System
The VR6 needs to be kept very cool as it runs scorching - this is due to both cylinder heads being directly on top of the engine block, which prevents the engine from using its water jacket to absorb and disperse heat.
The result is that the cooling system must be potent. In many cases, dual fans (one pulling air through radiator, one pushing air over condenser/heater core) are required for high-powered cars. However, even with such a setup, overheating can still become an issue.
Another problem with the VR6's cooling system is that it can become clogged up with carbon deposits which further restricts cooling and creates heating issues due to poor/restricted airflow around the engine. Unfortunately, cleaning out these fins is not an easy DIY task!
VR6 Ignition System
The VR6 ignition system was designed for the Porsche 928 and is different from the standard VW ignition system.
Rather than having a distributor on top of the engine, the VR6 uses individual coils on each sparkplug - this has some significant benefits, such as no wasted spark due to mismatched cylinders. The other benefit is that if one cylinder stops firing or misses a beat, the other cylinders will compensate and hopefully continue to fire usually.
However, there are some problems with this system in that it can be costly to replace/repair if one cylinder fails or has a misfire - not only do you need to purchase new coils but also spark plugs which can be very expensive for this engine. The other problem is that if your VR6 has a misfire, it usually is one cylinder which means you need to replace the entire set of coils for that bank - not cheap.
Another issue with the VR6's ignition is that it uses a different type of plug and wiring system - these plugs and wires can be tough to get and even harder to solder; replacing them is not an easy DIY task!
The VR6 engine was designed for transverse applications; it must sit behind the front axle line. The result is that either a cut or fold-down seat (to accommodate such high width) must be custom built-in in most cases which often results in uncomfortable seating for passengers. Furthermore, if you require occasional access to the luggage compartment during traveling, you will find it hard to do so due to interference from the bulky Vee-angle.
VR6 Engine Failure Mode
The VR6 engine runs very hotly, which can cause the crankshaft's failure - this is due to excessive wear on main bearings.
If you are getting black smoke from your car, it could indicate that your VR6 is overheating or running too rich - if so, do not ignore this problem as there are few warning signs before total engine failure resulting in an over-priced repair bill!
Another common issue with many VR6 engines leading to complete engine failure is improper driving conditions - the racing nature of the VR6 engine means it does not have any drive drag torque, unlike other standard Vee engines. Hence, it tends to rev high even at low speeds making the car difficult to control. If you are having trouble maintaining your vehicle, it could be the sign of a faulty ECU as this engine requires a larger throttle body and different ignition timing to make the proper torque at low speeds.
VR6 Engine Oil Consumption
The VR6 can suffer from oil consumption due to weak fuel economy and high revs, which means there is less force on piston rings and more pressure on cylinder walls - requiring a higher amount of motor oil. Special oil jets have been added to help with this problem, which squirts extra lubrication into needed areas only when needed.
There are also additional issues regarding poorly designed dampeners that can further cause damage due to poor support for the crankshaft or inferior gasket design, allowing too much oil to pass by - resulting in increased oil consumption.
VR6 Engine Performance Loss
The VR6 has a loud noise usually caused by worn-out or broken dampeners - if you are trying to fix the problem, your engine likely needs new dampeners, which are way too expensive for their good! Another reason could be a leaking gasket between the valve cover and cylinder head, resulting in serious oil leakages. If you find yourself replacing these parts, make sure to purchase OEM or high-quality replacements - otherwise, engine failure might be inevitable! Just keep in mind that the VR6 engine was designed to run at extremely high speeds, so many of its components were over-engineered, resulting in a significant depreciation of used cars.
There are also problems with warped heads resulting in misaligned valves, which causes uneven wear and usually results in complete engine failure.
VR6 Engine Misfire
If your VR6 suffers from a misfire, it can be faulty spark plugs, spark plug cables, or coils (which are all costly parts). The other reason could be poor fuel quality combined with high revs resulting in dirty injectors, which also need replacement - not the cheapest of repairs! If you experience engine hesitation or loss of power when accelerating, this is most likely a problem with the EGR valve and boost sensor, either of which needs immediate replacement. If your car hesitates on acceleration and stalls while idling, these problems might be caused by mass airflow sensors which are again known for causing issues inside the VR6 engine.
VR6 Engine Valve Train
The Dual-Vortex engine, as featured in some models of the Passat and Corrado, is not exempt from valve train problems despite its superior technology. Suppose your car is having trouble accelerating or driving uphill. In that case, it could be that you need to adjust timing by either adding shims under the camshaft or replacing shims with thicker ones if necessary - this will vary depending on model and year but usually requires removing the cylinder head and taking it to a local shop for adjustments. The other problem could be burnt valves due to poor oil quality - always check your car's manual for proper oil recommendations and change them regularly! Other issues might include belt tensioners which can cause problems such as squealing noise or loss of power.
VR6 Head Gasket Leakage
The first sign of head gasket leakage on a VR6 is usually white smoke coming from the exhaust pipe - the culprit will be either blown head gasket or cracked cylinder block, depending on the engine model. This problem can also cause excessive oil consumption in some cases.
VR6 Cylinder Head Removal
Removing cylinder heads on VR6 engines is a tricky process that can result in significant engine damage. If not done correctly, you need to be extremely careful when removing head bolts but avoid using excessive force as it might crack the cylinder block! Always use an expert for this task, especially when working with R32 or VR6 mk3 since these are very complicated models with additional electronics. Be sure to check with your local mechanic regarding injector o-rings, spark plugs, and coil packs which all have high failure rates, especially on early VR6 models.
VR6 Engine Block Repairs
The Passat B5 VR6 engine has problems with cylinder wall scuffing due to high engine speeds, resulting in engine block damage. Cracked cylinder blocks are also known for causing issues on R32 engines, especially when they are modified - if your car is overheating at idle and producing white/black smoke, this could be a sign of a cracked head or blown head gasket. Another common problem is leaking coolant, which will result in overheating issues combined with burnt oil smell - never ignore these signs unless you want to end up with a costly repair! Cylinder heads need a constant water supply to maintain pressure inside the combustion chamber. Otherwise, they can crack after several years resulting in complete loss of compression (a severe issue).
VR6 Valve Cover Leaks
If your car produces loud rattling noise at higher engine speeds, you might need to replace either the valve cover gasket or the whole valve cover. The newer models utilize a composite material that doesn't require any sealant and can be easily removed for valve adjustments without taking the entire engine apart. However, if you decide to do it yourself, please ensure that no dirt or oil enters the cylinder head, as even the smallest particles can cause problems later on!
VR6 Engine Mounts Replacement
Replacing broken/worn-out engine mounts will restore the proper operation of your VR6 engine and improve its overall performance, acceleration, and driveability. Worn-out rubber mounts indicate that the machine isn't properly isolated from road vibrations, resulting in misfiring issues, decreased fuel economy, and excessive vibrations.
VR6 Engine Mounts Repair
Bent engine mounts can be a reason for the reduced responsiveness of your VR6, especially when you're trying to accelerate at high speeds - this is caused by poor positioning of the engine block, which isn't able to maintain proper alignment resulting in uneven power distribution. Bent mounts usually produce loud banging noise from under the hood, so always check them before driving your car - if they are worn out, replace them immediately as they might cause severe engine problems!
VR6 Turbocharger Maintenance
One of the most common problems on older VR6 engines is their turbocharger failure, primarily due to poorly maintained cooling systems or oil leaks, which reduce their lifespan significantly. High operating temperatures combined with leaking oil will damage the turbocharger itself over time, resulting in decreased engine power and increased oil consumption. Always make sure to check your VR6 turbocharger when doing a regular inspection!
VR6 Injector Return Leak
Inspecting injector return lines is mandatory if you want to maintain good performance on your VR6. Otherwise, they can cause misfires and increase your fuel consumption at low idle speeds. Common signs of leaking injectors include trouble starting the car in cold weather, especially when it's wet outside or stalling issues caused by lack of compression - make sure to replace malfunctioning injectors as soon as possible since fuel delivery might eventually drop below critical levels wasting all your fuel instead of making it inside the combustion chamber where it belongs!
VR6 Throttle Body Gasket Leak Repair
If your car produces white smoke after driving for a while, lacks power when accelerating, or overheats too quickly, this might be caused by compound residue left behind on the throttle body gasket after it cools down. This is usually caused by oil residues transferred to the gasket, which block airflow resulting in misfiring issues and reduced engine power. If you have fixed this issue yourself, please let me know what method worked best for you so I can pass this valuable information to our other readers as well - thanks! 🙂
VR6 Throttle Body Replacement
Replacing the whole intake manifold would be a costly procedure. It's AVL-manufactured, so you might want to return only your throttle body if it's damaged or poorly maintained. Replacing the whole thing is a very complicated and expensive procedure, and in most cases, parts aren't available, so do it at your own risk!
VR6 Camshafts Replacement
Replacing worn-out camshafts can cause poor performance on your VR6, especially when it comes to low-end acceleration - this is caused by increased engine wear which occurs due to misfiring issues resulting from poor valve timing (when valves don't open and close at the right time). If you're experiencing lazy starting, lousy gas mileage, or irregular idle speeds, make sure to check your camshafts for excessive play and order replacements before installing them yourself - replacing them is a very complicated and risky procedure, so I wouldn't recommend you do it on your own!
VR6 Intake Manifold Gasket Leak Repair
VR6 intake manifold gasket leaks usually result in reduced engine power, overheating issues, and trouble starting the car - its lower side will also be covered with coolant, which might damage the turbocharger if it isn't replaced in time. We recommend inspecting this gasket when doing an oil change, and if it's damaged, replace it immediately as cooling problems might occur soon due to reduced heat dissipation where they can cause severe engine damage!
Measuring 6-Cylinder Engines
The VR6 engine has no 'standard' way of measuring the machine in terms of cubic centimeters - this is mainly because there was no reference point given in the factory, and variations from model to model or even within a model can be pretty significant.
In terms of measuring the actual bore and stroke, many people have used various measurements, including:
- VW Measuring Block (Which uses a steel ring with 12 holes drilled into it, which you then use a pin gauge to measure)
- VW Camshaft (Where you use the 'keyway' on the camshaft to measure - this is unreliable as it depends on how much of the keyway has been machined off and can vary between engines)
- VW Calibration Plug (The plug is usually located next to the EGR valve and is threaded into the block - VW has a unique tool to remove and measure)
- VW Manual Transmission (This uses hardened steel pins which you push through the flywheel)
The VR6 also has various other related measurements such as 'flats' or spaces between cylinders - this is usually measured from the case of the engine to the top of the cylinder.
To give you an idea of these variations, here is a list of engine block measurements taken from various VR6 engines:
- 180HP (Mk2 Jetta) - Intercooled: Measured at 173mm
- 200HP (Mk2 Golf / Bora) - non intercooler: Measured at 178mm
- 200HP (Mk3 1.8T / GLI 16V): Measured at 176mm
- 230HP (MK4 Jetta): Measured at 168mm
- 250HP (B5 Passat): Measured at 167mm
The above shows no consistency between models and variants - even within variants, there were often significant differences.
It is also worth noting that several different types of VR6 engines were produced - the first one being the 'VR' engine, which was later replaced by a 24V version, followed by a 20V version before finally ending with the 'MR' or narrow-angle V6.
Some rare 'specials' were made, such as 12-cylinder VR6's and even three-cylinder variants made for industrial use!
As long as you know the basic engine measurements and how to measure camshaft play, I would recommend not worrying too much about block deck height or any other size - ensure that the engine is well looked after and maintained, and you should have no problems!
Although the VR6 has a lot of potential for performance tuning, it's scarce to find any 'tuner' engines due to their poor reliability when pushed to the limit. Suppose you do, however, plan on doing so. In that case, we thoroughly recommend getting hold of a service manual (which will also cover the 24V variant) along with plenty of spare parts such as gaskets, oil filters, etc. - these are generally cheap but will be invaluable when doing any serious work.
In most cases, an engine rebuild will be required every 100k miles or so - however, this depends on the engine's condition and how many components have been worn down. A lousy turbocharger, for example, could mean a new machine is needed before the block has reached half its life!
Lastly, if you will use your VR6 as a 'daily,' then we highly recommend installing some form of oil cooler as extended idling in traffic can cause quite noticeable heat build-up - even with mild idling problems, it is still possible for over-heating issues to occur. This problem isn't just limited to VW/Audi cars either - Benz and others have had Turbo Diesel engines that suffer from the same pain!