Is the S14 reliable?
We rate the S14 72 of 100 for reliability: good. The rating is one of the inputs to every Guide Score below, and it is argued for on the method page with the others.
Why that rating
The lit mark is the S14; each grey mark is another engine on the engines page.
The E30 M3's race-bred 2.3-liter four is durable when maintained, and Hagerty's price guide says the car asks little beyond valve adjustments and the odd valve cover or oil pan leak.
The known items are the solid-lifter valve adjustments, a timing chain tensioner that rattles on cold starts, oil leaks, exhaust manifold studs and, on some engines, porous heads that leak coolant into the exhaust ports.
Parts made only for the S14 are expensive, and a rebuild costs far more than it would for a regular BMW six.
Cars in this guide with the S14
| Car | Years with this engine | Reliability | Guide Score |
|---|---|---|---|
| M3 E30 | 1988 to 1991 | 63 | 79 (1991) |
Reliability is each car's score out of 100 for the years it had this engine: the engine rating plus that car's own known problems, service costs and age. The Guide Score is for the car's best year to buy.
Known problems on the S14
| Problem | Named in the guides for | Typical bill |
|---|---|---|
| Oil leaks and exhaust manifold studs | M3 E30 | $600 |
| Timing chain tensioner | M3 E30 | $400 |
Bills are the guides' estimates, not quotes; each car's guide says which model years a problem hits and how to check for it. The bars share one scale, up to the costliest bill here.
Other engines
Every engine we rate, from the most reliable down, is on the engines page.