Hey all:
My 16v AC has been converted to r134a, but it does not cool as well as it could. I was just wondering if new hoses from the dealer are barrier hoses, which are practically a necessity for r134 conversions due to the different size of r134 vs. r12 particles, or if they are just the original rubber ones. Thanks.

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1985 190E 2.3-16 Euro

M-B does indeed use barrier hose in replacement hoses and manifolds for vehicles that were originally equipped with R-12 refrigerant systems.

And they've done away with R-12 calibrated expansion valves... only R-134a calibrated valves are available.

This probably has little if anything to do with your reduced cooling. The best of conversions to 134 will only have 85% of the original cooling capacity. Some of this can be recovered by using a higher capacitor condensor, but going to that expense is false economy, since you could simply charge it with R12 for less than $100 difference.

Most original hoses will leak very little 134 because they have built up a coating on the inside of the hose from the mineral oil that circulated through the hose.

To begin with I would put on gauges and see that the system is charged properly. If not, charge it. If so, and you want greater cooling, reverse convert to R12.

If you are bent on thinking that the hoses are your problem, any auto a/c shop can simply replace the rubber on your existing hoses and make them look like new for probably 25% the cost of new hose assemblies from MB.

My $0.02,