99 s70 2.3T New Project Car

[yanga001]

Hi everyone,

We recently purchased an s70 2.3T as a parts car, but it turned out to be a gem. Car runs, AC works, engine shows no sign of rust or dirt (someone really loved this car). Its a 99 model, and the front callipers or pins are seized (will be working on it over the weekend to confirm which one) and it seems that nothing mechanically is wrong with it.

We had a 98 v70 N/A so i am quite familiar with the quirks and follies of the naturally aspirated engine, but i am not as familiar with the turbo's.

From what i have heard, we should check on the oil consistently, check seals, and check the ETM module (electronic throttle controller) for signs of wear.

From the minimal driving done on it, i didn't feel any issues with the engine, or hear anything that sounded out of the ordinary. In fact we found that the 2.3T was quieter than our N/A v70. I attributed that to a proper muffler and a rust free, hole free exhaust system.

If we replace the front callipers, should we also replace the rotors or have them refaced?

Also the passengers chairs motor sounds seized or disconnected, has anyone disassembled the chair or tried to rewire it. From our point of view, if we get a replacement motor or check the continuity and repair any disconnects then it should work right?

Thanks in advance, i have been using this forum for a while and have found it to be a great resource for all repairs.

Can post pictures if requested.

[bmdubya1198]

I would just do the normal checks for these cars, timing belt, PCV, etc. If the cam seals look suspect, replace them. And only run premium gas, lower octane fuel has been possibly linked to burnt valves.

If you replace the calipers, I would definitely recommend new or resurfaced rotors, and of course new pads.

[Eddystone]

"And only run premium gas, lower octane fuel has been possibly linked to burnt valves."

Could I get some feedback from several people on whether or not this is a generally agreed upon statement?

I have a '99 T5 and use mostly regular octane gas in the USA rather than premium, so I'd like to know if this a recognized fact.

[RickHaleParker]

Also the passengers chairs motor sounds seized or disconnected, has anyone disassembled the chair or tried to rewire it.

Which one?
1. You can hear/feel the motor trying but the seat does not move.
2. You can hear the motor running but the seat does not move.
3. Motor does nothing.

[Sommerfeldt]

"And only run premium gas, lower octane fuel has been possibly linked to burnt valves."

Could I get some feedback from several people on whether or not this is a generally agreed upon statement?

I have a '99 T5 and use mostly regular octane gas in the USA rather than premium, so I'd like to know if this a recognized fact.

Low octane can cause abnormal combustion, and is far more likely to do so as boost pressure increases. Those "abnormal" combustion problems can cause burned valves. The higher the pressure, the higher the octane is the main guideline, afaik... that's also another reason to run ethanol/E85 in performance applications - that stuff is 105, if I'm not mistaken.

- S

[bmdubya1198]

Regardless, being a turbocharged engine I would only run premium anyway. Fortunately around here 93 octane isn't too expensive (about $3.13/gallon currently at my preferred gas station) so it's cheap insurance. Plus it pulls a little more power out of it. You'd be amazed at how much of a difference going from 89-93 octane makes in my brother's Miata! It feels like a different car!
The risk of preignition under boost isn't worth it to me to run lower octane. This goes for any turbo engine, not just these Volvos. A lot of newer turbo engines are designed to run on 86/87 octane, but the engine management is smart enough to compensate and adjust timing and whatnot. M4.4 and ME7 can't do that to the same extent, as far as I know.

[yanga001]

Also the passengers chairs motor sounds seized or disconnected, has anyone disassembled the chair or tried to rewire it.

Which one?
1. You can hear/feel the motor trying but the seat does not move.
2. You can hear the motor running but the seat does not move.
3. Motor does nothing.

When we flick the switch motor does nothing. ill take a look at it over the next few weeks. I hope its just a bad connection or something to that effect. Ill bring up a multimeter and check conductivity to confirm. I assume its just a DC motor so further resistance tests can confirm if it is functioning correctly.

[Eddystone]

Well, the owner's manual that shipped with my 1995 S70 T5 states that 87 is the minimum octane requirement and that to obtain "optimum performance" use 91 octane or higher. I have always taken that to mean that Volvo is stating that you can use 87 octane without causing problems to your engine, either short-term or long-term and that if you want every one of those 236 horses you need to use premium. I know that we all have certain areas where factory recommendations are taken as Gospel, other areas where we know full well that they are BS of the CYA variety, and still other areas where we know it's best to EXCEED the factory recommendations.

Right now, in my area there is a $0.44 difference between regular and premium which is maybe $8.00 per tank for a small car that only reaches MPGs in the high 20's at legal highway speeds and much less around town.

I'm just asking whether or not anyone has any real evidence that a particular Volvo engine in STOCK configuration will burn valves from using 87 octane gas, or whether it's nothing more than talk. I have no problem spending the extra cash if there's any scientific basis that using less than 91 octane will damage your Volvo engine.

I'll also grant that using premium may yield something like 3% better mileage which reduces the extra cost. Still, I'll bet burned valves has more to do with how hard you push your engine. I spend most of my highway time at 2600 rpm and seldom hit 4000 rpm. Yes, I'm an old fart and get plenty excited by 4000 rpm. I have been thinking about what someone wrote about the valves not rotating on their axis until you hit 4000 rpm and that you should at least periodically run your engine at 4000 rpm for a period of three minute. I should do that, but it might be too exciting...

[Sommerfeldt]

My ‘74 Ford Escort Mk 1 was made to be able to run on kerosene and chainsaw oil... I still gave it 98 leaded, as it was called here, and then 95 with additive when the leaded stuff disappeared.

- S

[RickHaleParker]

I hope its just a bad connection or something to that effect.

Good chance it is a wire broke off at the connector or the switch PC board