I'm about to change from Delvac 1300 15w40 to a synthetic (Mobil 1 Truck/SUV) 5w40 in my '85 300SD. I live in San Antonio, so I'd like to know how it holds up to the heat as far as viscosity goes. I don't have any leaks...occasionally I will have a bit of seepage around the oil cap or valve cover blow-by hose after some really spirited driving. So the syn shouldn't cause any right? The car has close to 238k on it and it's a great ride and a beauty.

Just want to know what others have experienced after going syn.

PS-I passed a great deal on Rotella syn to go with the Mobil 1.

Thanks all!

SSSS OK inna Dallas heat fer me.

Regards

Run-em
1983 300 S D - aka.- SPARKY THE DIESEL

Used it in Dallas for 2 years and 30,000 miles and had great success. Now live in RI and will continue to use it.

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14 E250 Bluetec 4Matic "Sinclair", Palladium Silver on Black, 154k miles
06 E320 CDI "Rutherford", Black on Tan, 172k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver on Tan, 142k mi, wastegate conversion, ALDA delete

19 Honda CR-V EX 63k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife

This is a very good oil choice for our North Texas climate.

Have a great day,

Yup, I run 5w-40 or 0w-40 in everything from cars to vespa motorscooters. Works great in Dallas year round. You'll want to stick with the 5w-40 because it's got the latest compression engine certifications, the 0w-40 doesn't.

- JimY

I switched to Mobil-1 Truck & SUV Synthetic and have not had any oil leak problems. You should be aware however that Synthetic oils do contain additives that will disburse accumulated sludge. If the sludge is all that has been keeping your seals or gaskets from leaking, then yes, you may see some small leaks. Big leaks mean the gasket or seal is probably ready for replacement.
The good news is that synthetics also contain additives that soften and slightly swell old seals so any small leaks will probably seal after a more use.

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1991 M-B 560SEL Arctic White/Grey 99,000 Miles
1987 M-B 300SDL Ivory/Palomino 229,000 Miles (sold but never forgotten)
2006 Volvo XC70 Blue/Beige
1999 Porsche Boxster Arena Red/Savanna Beige
1986 Porsche 928S Goldweiss/Brown

Yep, needing real heavy oil in hot temps is an old wives tale left over from the days of dino.

5w-40 is just fine for year round use. Heck GM runs 0w-20 in a bunch of their engines, and MB factory fill has been 0w-40 for years.

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1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200

where is a good deal on the mobil1 to be had in SA? truck stop? deal me in as i need a good source too


john

The 5w40 truck&SUV Mobil one is the same as Delvac one. Walmart sells it for around $20 for five quarts.

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'79 300SD W116
'86 190E 2.3-16V W201
'92 300D 2.5 W124
'99 E320 4MATIC S210

The second number (40) is how it performs in warm weather, 5W-40 or 15w-40 should perform similarly in the summer.

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1986 190D, 2.5L, 5-speed swap, 180,000 Miles (60K by me).
Jeep CJ-7 with Cummins 4BT/NV4500/AtlastII 4.3.
Grand Wagoneer 4BT project in progress!

Walmart sells it for $20 for 5 quarts. Sometimes Pepboys has M1 on sale for $3.99 a quart but they usually limit you to 6 quarts and don't have Delvac 1.

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1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200