This is my first time ever posting here. I'm not very mechanically inclined, I just want to have some ideas of what's wrong before I ask a mechanic.

So there's three possibly separate or related issues with my 1998 S70 GLT. The radiator was recently (about a month and a half ago) replaced due to a hole that was poked in it. As far as we know, the car never got too hot, even though it was gushing radiator fluid, we noticed immediately that the temps were higher than normal and stopped very frequently on the drive home and to the shop to add water so the car didn't fully overheat. We didn't think that it caused further damage but maybe it did? Since fixing the radiator, the temps have been normal (and even before, we never let it get into the red part of the gauge) and no fluid leaks that we have seen.

So now, the car intermittently does not start. It doesn't turn over, it does nothing. We've checked the voltage on the battery and everything there seems to be fine. When the keys are in, the lights all come on at normal volume, but when the key is turned, we hear a clicking noise and all the lights shut off until the key is returned to a neutral position. Then, other times, it will start up no problem. Literally like there was nothing ever wrong. This has been going on for about a week.

Then, over the last 3 days or so, it has started idling extremely rough. When we can get it to start, it tries to die immediately, but even if it does, it will start right up again, but then die on idle. If I apply gas during this time, it stays alive and doesn't feel rough. After running for about 10 minutes it idles fine again, and I can drive in city traffic without worrying about it dying. But only if I can get it to start.

Two days ago, we really started questioning what the issue was because we realized the other things weren't flukes, and we noticed that it was almost entirely out of oil, and the dipstick came out sludgy and caramel colored. We got an oil change less than 1k miles ago, and prior to the oil change we hadn't gotten the oil changed in probably 5k+ miles, but checked and filled the oil regularly without any issues.

So my question is, are these issues related? I don't know much, but the starter issue feels very unrelated to the other two. We have limited tools, is there anything we can do to test things ourselves? Is it possible that in fixing the radiator or changing the oil, they allowed moisture into the engine which is causing the sludge?

 

Since you're not mechanically inclined there's not a lot you can do. The main thing I would suggest is finding a good indy shop that knows volvos (this model) and give them all the good info you just gave us.

If the starting problem happens pretty regularly, then they should be able to diagnose it quickly; if it's more intermittent, it will be more difficult. Could be starter motor, battery cables or connections, PNP transmission switch, ignition switch, or any number of other things.

I'd also be concerned about your sudden oil consumption; change the oil asap and monitor it's condition and level closely.

How many miles on the car? How long have you owned it? Other than the radiator what kind of service have you done to it?

 

I doubt a rad change has anything to do with other problems. The coolant system is pretty much independent. Just like the fuel system is from the oil system.

Have you had the PCV system changed lately, my guess is that you have a good oil leak under pressure somewhere. If not, you'd be seeing smoke out of the tailpipe.