Tech Tips: Oils and Fluids

Engine

The original manual prescribed SAE 10W-30 / API SC or SD motor oil. Today such oils are only produced for classic cars and, generally, there is no point in using these in the Volga engine – more modern oils which are still widely available on the market work just as well, or better.

Use SAE 10W-30, 10W-40, 15W-30 or 15W-40 / API SF, SG, SH or SJ motor oil. Oils with lower ash content (<1 %) are to be preferred. Change oil at least every 5 000 kms.

The Volga engine is not designed for the modern oils, especially the earlier modifications which use a road draft tube for crankcase ventilation, which is inefficient at high engine revolutions and allows significant oil oxidation. It also does not need the additional protection provided by modern engine oils because it is a low-revving, under-stressed engine designed to run happily on the oils available in the USSR back in the 1960s (something like API SC & SD, often worse than that in practice). The use of modern oils with high additive content, especially diesel oils, is known to cause rapid sludge & deposit build up and increased wear. Fully synthetic oil is known to cause leaks, its use requires a complete replacement of all engine seals.

gaz24_oil_filterThe full-flow oil filter is of the type with a permanent housing and a replaceable filter element, much like in some modern German cars. 24-1017140 filter element is still produced and available in the former USSR countries. Can be substituted with Mann H727/4 and analogs. Don’t forget to soak the filter element in oil before installing and drain the sludge by unscrewing the drain plug located on the lower portion of the filter housing. As an alternative, adapters for modern, spin-on style oil filters exist, they are available via classic car parts dealers in Russia. Modern filters work better with modern oils.

The Volga engine uses a rope-type rear main crankshaft oil seal. Modern motor oils, especially synthetic, may cause significant oil leaks on engines with old, worn-out seal. A known replacement part available worldwide is Mercedes-Benz A0019971241 Crankshaft Oil Seal (needs to be slightly shortened, but overall fits just fine). Front crankshaft seal is of the ordinary type.

Transmission

Use SAE 75W-80, 80W-85 or 80W-90 / API GL-3 (originally specified by the manufacturer) or GL-4 (widely available modern analog) transmission oil in the gearbox and API GL-5 / Hypoid transmission oil in the rear axle.

DO NOT use GL-5 oil in the gearbox, this may cause hard, noisy shifting and premature wear of the synchromesh.

Hydraulic systems

Volga cars built before 1985 had their hydraulic brakes and clutch operating systems filled with Castor oil-based crimson brake fluid named BSK (DOT-2 analog). It is not interchangeable with, nor can be mixed with, any other types of brake fluids.

This type of brake fluid was used in USSR/Russia well into 1980s and even 1990s, and was actually good for what it was designed for, namely – drum brake systems with a low level of heat generation. It is no longer in production because it cannot be used in cars with disk brakes due to its relatively low boiling temperature.

DO NOT use any other type of brake fluid unless all and every rubber part in the system is replaced with a brand new one ! DO NOT mix Castor oil based and Glycol based brake fluids ! In both cases the hydraulic brakes system would be rendered inoperative (either instantly or in some time). Mineral oil based brake fluids are also quite lethal for the rubber used in these systems.

If the level of the fluid in the brake or clutch master cylinder reservoir filled with the crimson brake fluid drops “in the field”, top it up with pure castor oil (available via drugstores / pharmacy stores), that would lower its boiling point a bit, but the brakes will continue functioning properly. Butyl alcohol (butanol) is also good for this purpose (but somewhat harder to get). Ethyl alcohol (ethanol) can be used as well, but it evaporates relatively quickly, causing the level of the fluid to drop, and also has a lower boiling temperature than butanol.

The applicability of silicone-based brake fluid (DOT-5) is still in question, some owners have experienced compatibility issues with such fluids.

GAZ-3102 (front disk brakes), GAZ-24-10 (either disk or drum brakes) and other later Volga models use standard Glycol-based DOT-3/4 compatible brake fluid.

Note: some of the cars may already have been converted to DOT-3/4 brake fluid – check the brake master cylinder and clutch actuator reservoirs for what type of fluid  they are filled up with. Castor oil based brake fluid is crimson to orange and has a very specific odor; DOT-3/4 is transparent or yellowish and almost has no smell. It is even not uncommon that clutch actuation system and brakes hydraulic system use different types of fluid !

Chassis lubrication

Use any light transmission oil.

GAZ-24 Volga, unlike many cars with kingpin type suspension, has its kingpins rotating in needle roller bearings, not bronze bushings, and these bearings should be lubricated with light oil only. DO NOT use consistent greases, or else the lubrication paths would get clogged up very quickly and you’ll have to disassemble the whole unit for cleaning (the lower trunnion is especially susceptible to this because it is lubed through the same grease nipple as the lower kingpin bearing, and therefore the grease has to pass at first through the bearing itself, and then through a long and narrow channel drilled in the steering knuckle support, which is prone to clogging; adding a separate grease nipple for the lower trunnion is a good solution to this problem).

It may be possible to substitute light oil with the type of lubricant used in centralized lubrication systems on trucks / trailers / buses, but use it at your own risk.

Cooling system

The Volga’s engine has an aluminum alloy block, so make sure the antifreeze you use is fully compatible with aluminum alloys. Use of water as coolant is inadvisable, as it is known to cause extensive corrosion due to the presence of aluminum / iron galvanic couple (it has been used by many owners back in the day, but that is a bad practice which slowly but steadily causes irreparable damage to the engine block and cylinder wet liners; distilled water may be used with a good corrosion inhibitor, but do that at your own risk).

On pre-1985 engines (ZMZ-24D and 2401) the cooling system pump must be regularly lubricated with Lithol-24 brand or any other Yellow Lithium grease via a grease nipple (every 12 000 kilometers, according to the Manual). Use a grease gun; continue pumping the grease until it starts to be squeezed out of the control hole on the housing. Remove the excessive grease to prevent damage to the belts and other rubber parts.

If you do not have access to the above mentioned sorts of grease, or wish to use any other type of grease (which is only appropriate, because much better greases are available today than Yellow Lithium), disassemble the whole unit, clean it and fill with the new grease.

On engines built after 1985 (ZMZ-402.10 & 4021.10), the pump bearings are lubed for life at the factory and in theory do not need any additional lubrication (some pump housings still have a threaded hole for the grease nipple, but no nipple itself, just a plug).

In any case, consider disassembling the pump and replacing the old grease, because it is usually in unserviceable condition basically because of its age. The bearings themselves and the rotor are also usually in bad shape and should be replaced. GPZ 20703 bearings were originally used, internationally available analog is 65203 RS.


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