1998 S70 A/C Compressor won't kick in on its own

[TripWyre79]

Perhaps just a new higher amp alternater and a MAF sensor cleaning?

[Ozark Lee]

Okay, I'll see if I can get one from pull-a-part this weekend and test it out. If I may encroach on your knowledge a bit more. The car has had a couple other little things i had wanted to ask about. The first being the alternator. I've noticed as the car is running for long periods of time it starts putting out less and less voltage. Starts at around 13.7 v and by the end of my trip to work. It's at around 12.7. If I need things like headlights and windshield wipers it's even lower usually sits at around 12.4 12.3 V until the following day when I turn it on and it starts back up at 13.7 V. I know that's low in the first place, I think I heard somewhere that the alternator voltage shouldn't be below 14 volts. Addition to that whenever I coldstart my car, it idles pretty poorly, sometimes so low it acts like it's about to stall and has stalled on occasion, but after about 5 to 10 minutes of driving it idles perfectly normal. And last but not least the seat heater only seems to work when I first turn the car on and will only stay on for about 7 to 10 minutes and then turn itself off even with the switch still activated, and then won't work again until the car has cooled down being turned off for a while. Any ideas on where to start looking on some of these issues, any advice would be greatly appreciated and thank you for your help so far.

I would start by removing and cleaning the battery terminals really well. You may have an alternator problem but when they go they tend to go big and quit altogether. There are some intermediate failure modes but they are not what would fall into the common category. The battery cables are a known weak spot, particularly the B+ cable to the fuse box, but that manifests itself more with weirdness in the cabin than the battery not charging. Cleaning and scraping the terminals is something you can do and it is free. From there you should probably visit one of the chain auto parts stores and have them test the alternator and battery. They can load test the alternator in the car with the new computerized testers. Keep in mind that they are in the business of selling auto parts though and try to get the raw numbers from them and post them back before you buy a new alternator.

As far as the near stalling and rough performance when cold goes, the fact that it occurs when cold suggests a problem with the ECT sensor. It could be a MAF problem but they really aren't temperature sensitive. Do you have a check engine light and have you had the codes read? If you have codes it goes a long way in helping to figure things out. That is another place where the local auto parts store can help you out but be sure to get the actual Pxxxx number rather than their description of the error.

The seat heaters have two variants of thermostats, one type is stuck up in the bottom cushion and the other type is a black box that is attached under the front lip of the seat. Other than the wires falling out of the type in the cushion they tend to work and stay working but they let things get too hot and many were swapped out to the external box variety. I have no real experience with the external variety and I don't know firsthand what makes them tick or how problems with them present. Perhaps another member can help you out better with that one.

...Lee

[TripWyre79]

Thank you for the advice. At this point I've been able to resolve all of my issues except the seat heaters one. But it being spring and about to be summer in the Carolina's. A heated seat isn't much of a priority. Okay so essentially I've done a stage-0 tune up and the difference is insane. I haven't put it on a dyno or anything but it feels like a new car. So what I've done so far: I've replaced all of the spark plugs with Bosch copper Cores, the ones that were in there appear to have burned evenly but the center portions were really worn down. I cleaned the mass airflow sensor really well with mass airflow sensor cleaner, I added a new K&N air filter. I found that the airbox hot air/cold air thermostat was stuck in the hot air position, so that kind of explains the dogging after the engine had warmed up. I modified that to be about 90% cold air and 10% hot air, as the average ambient temperature is at least 70° around here, and in the winter it rarely ever drops below 36°F so I don't believe the hot air intake needs to be open.I cleaned the battery terminals and cables really well with a terminal cleaner and wire brush as well as the B+ line to the fuse box. I got a new distributor and cap/wires. I got a new A/C compressor relay and replaced the high pressure sensor, a friend of mine has a garage and A/C repair equipment, and owed me a favor so I had him vacuum out the line and check for leaks, it did have one leak but we repaired it, and the AC now works flawlessly and can get so cold it'll give you a headache. I had to replace a few vacuum lines due to being dry rotted and cracked. I did a Seafoam treatment with 1/3 in the fuel system, 1/3 in the oil system, and the other 1/3 in the vacuum system. I was extremely careful not to Hydro-lock it. The amount of white smoke my Volvo put out was amazing, I drove it about 8 miles with an even mix of city and highway, I stopped by The auto parts store and got an aluminum washer and a new oil filter and I changed the oil. It seemed like there was a good amount of deposits in the engine as it just rolled over 130,000 miles, so in about 200 miles I'm going to do another oil change just to make sure I get any remaining deposits out. I know this all was kind of a aggressive tuneup strategy but I just got a promotion at work and a really nice pay-raise and wanted to do a nice little restoration on my Volvo. The Volvo holds sentimental value to me so I didn't want to just trade up for a newer one, however I do wish the engine was a GLT or a T5. I also wish it was a manual transmission. The performance in this car after the stage-0 tuneup has really made me appreciate these cars more, I would like to continue upgrading but I know there's only so far you can go with an NA engine. All in all, these steps translated to a significant increase in throttle response time and acceleration as well as completely resolving my poor idle issue and charging issue. Due to the sentimental value of the car, I don't want to get rid of it, but I would really like it to have a T5 with a manual transmission, my question now is, is it at all possible to switch this engine out for a T5 with a manual transmission and how difficult would it be. Cost is not a huge issue and I do have other vehicles if this has to be out of commission for an extended period of time. It might be fun to drive the 65 impala ss to work for a few days if a swap is possible for the Volvo. And if not swapping. How difficult would it be to mod this to a GLT or T5 engine. I'm sure things like ECU and other computer components would need to be changed too. Any advice anyone might have as to making these changes would be greatly appreciated. If you could include cost options, compatibility, ideas and insights. As well as what supplies I might need. I'd really appreciate that as well. Let me know. I'm open to all options and ideas. Sorry for the long reply, but Thanks in advance.

[Ozark Lee]

My question now is, is it at all possible to swatch this engine out for a T5 with a manual transmission and how difficult would it be. Cost is not a huge issue and I do have other vehicles if this has to be out of commission for an extended period of time. It might be fun to drive the 65 impala ss to work for a few days if a swap is possible for the volvo. And if not swapping. How difficult would it be to mod this to a GLT or T5 engine. I'm sure things like ECU and other computer components would need to be changed too. Any advice anyone might have as to making these changes would be greatly appreciated.

Nothing is impossible but it really isn't practical. The engine would need to be changed or you would need to do a complete teardown and change the pistons and the exhaust valves. The exhaust to the center of the car, including the downpipe and catalytic converter would need to be changed. The entire harness under the hood needs to be swapped, the ECU would need to be swapped and you would need to get the ECU re-burned to be compatible with the manual transmission. Additionally there are wiring changes that need to be made inside the cabin to get the climate unit to work properly. There are other things that need to change as well but they are just completely different under the hood.

Congratulations on getting the other stuff squared away.

...Lee

[TripWyre79]

Thank you Lee, You and the Forum were instrumental in assisting me throughout. So again, Thank you!

As the the practicality, It sounds like its more Ideal to just fully swap all mechanical components from a T5 to mine rather than rebuilding the current engine into a T5, Would you agree there? Like, essentially put my cars Cabin behind an existing T5, then just some rewiring. For instance, Take every engine component out of an existing T5 and place in my bay? I am a logical person and I know it makes way more sense to just trade it for another with a T5, and if it weren't for the sentimentality behind the car, I likely would have done that already. That's my only hesitation.

Sentimental back round:
It and the Impala were my fathers, 2 years ago I fell on hard times and my dad gave me both cars. The Volvo for reliable transportation and the Impala being a generational thing and a restoration project. My grandfather got it new off the line. My father was then killed in a car accident the week after giving me both cars

That's why I was leaning more into keep the car, but upgrading the engine as I know the potential for the T5's are almost limitless.

[Ozark Lee]

It will cost you at least twice as much to try to do a turbo swap as it is to just buy a turbo car to begin with. Add to that the cost of the manual swap which will be another $1200 to $1500 on top of that by the time you by a "swap kit" and get Lucky at ARD to burn you a manual ECU.

The problem you will find is that manual T5s are unbelievably rare. That said, they are out there and I had one locally for sale a couple of months ago. I can't remember the asking price but I think it was around $2000, maybe a bit more. I thought about it and went as far as to make a phone call but he sold it before we could arrange a time for me to see it.

...Lee

[TripWyre79]

Oh darn. For that price and specs I would have brought cash in hand right then and there. Okay. I'll keep my options open and look for a turbo manual. If I find a deal like that I'll jump at it and worry about the swap options. If any. Later on. If anyone comes across a 98 s70 T5 manual in the Carolina's region for a decent price. Please let me know.

[abscate]

There is a T5M coming up for sale in ON Canada per the other thread!!

[as400jockey]

I have a 1998 S70 Sport. No turbo. A/C had been acting strangely - compressor kicking in, then quickly off, then repeating. Felt like low refrigerant. When the car is cold, pressure in the system is about 80PSI. So it's not empty.

A week ago the ECC was dead, as was the sunroof and instrument panel lights. A 10A fuse blew. Replaced it. Everything else works except the a/c. Blend doors, heat, fans... all good except a/c compressor won't come on.

Low pressure switch is working. Shorting it out changes nothing. Replaced the high pressure switch. No changes. If I short the compressor pins on the a/c relay, the compressor comes on OK, sounds good, gets cold. Replaced a/c relay. No change.

As far as I understand it, there are no other sensors to worry about... it feels like the ECC is the culprit. I removed it. Nothing fried that I can see. My guess is that the cause of the fuse blowing was the ECC, and that the ECC is causing this current headache. But I don't have a spare to play with. I can get on on eBay for about $50, but that's an expensive guess.

Just now I connected a freon recharge kit to the low side. About 85PSI with the engine off, about 80F. Started the car. Shorted the a/c relay pins. Compressor came on. Low side pressure dropped into the 40's then continued into the 20s. THAT feels like low refrigerant. So I let it charge. It started getting cool in the car. After a few minutes I got a hissing noise. Dunno if it was a leak or the clutch slipping. I pulled the jumper. I think it was the clutch. Maybe now I'm overcharged?

I let the car sit a half hour or so. Jumping the clutch relay working OK. compressor sounds OK.

Before I spend that $50, does anyone have any other ideas?

[as400jockey]

Figured it out...

I replaced the high pressure switch. Nope. The AC relay. Nope. Shorted the low pressure switch. Nope. Replaced the ECC module (in the dash). Nope.

I pulled the ECM, cleaned the contacts, let it sit for a few minutes for any memory to die, reinstalled, and voila! Compressor kicks in now.