When the engine began to surge at idle, I corrected air leaks then followed the Bentley manual to check the resistance in the LH -2.0 AMM heated Platinum wire. My test revealed a resistance of 4.5 Ohms. Bentley advises replacing the AMM. The acceptable range is 3.5 - 4.0 Ohms. I'd like to know what causes the resistance in that wire to increase over time? What remedies, if any, exist for this situation? Is spray cleaner of any use on this AMM? Following a tip, I have just invested in a Bosch Automotive Handbook for future reference.

Rockauto indicates that Cardone offers a return and rebuild service for my AMM: https://www.rockauto.com/en/moreinfo...t=5128&jsn=834. Does anyone have any experience with this service?

Any suggestions for correcting the surging problem and restoring proper idle would be greatly appreciated! Thank you very much!

 

Cleaning it doesn't work. Testing it doesn't work as far as I know. Rebuilding them may be OK, depends, and you hear all kinds of stories. RPM surge is a rare symptom of a failed AMM but who knows, these things are tricky and cause all kinds of issues as they age. Many "new" ones are bad. I am a big DIY guy but I never tried to get into an AMM.

 

Thank you very much for sharing your experience and thoughts! While I would like to resolve this problem ASAP, I am too ignorant of the mechanisms of function and failure of AMMs to be able to make a truly well informed decision about how to proceed. I'm going to wait until I'm better informed before I make a decision. Hopefully the Bosch Automotive Manual that I have ordered will prove to be usefully informative.

As a senior member, you should be in a position to advise me about parts availability for 240 series Volvos. I very much like the vehicles and would like to get a 244 as a replacement for the '91 Olds Cutlass Calais that was given to me and that I been keeping operational for ten years, but I'm concerned about parts availability for the 240s. Years ago, I was surprised when Pierce, the forum moderator, advised Toyotas instead of Volvos! Again, I should like to express my gratitude for your thoughtful and helpful reply - It is greatly appreciated!

 

AMM are indeed a problem which will only get worse as the Red Blocks age. They are hard to diagnose and throw all kinds of codes which may or may not make sense. Once you have a good AMM on it's like night and day, you immediately know it! Been through that several times. Rebuild from a reliable source should be OK, "should"...
Mechanical parts availability is no problem and won't be for a long time--older Volvos are plentiful and share many parts over the years so that makes it easier. More problematic are body and interior, trim, etc. Most are NLA new but still plenty of recycled ones out there.

As far as Toyotas (I used to hate them), I am a big fan now--it's the only newer brand I'd be interested in and right now my daily driver is mostly a '04 4 cyl. Camry XLE, can't beat it! I am down to two Volvos (had as many as 12) and I will hang onto them as long as I can for old times sake. I have been into Volvo since 1986 when I bought a new 740 Turbo Sedan with a manual tranny. European cars have become money pit nightmares designed to last 60k miles before major and very costly repairs come due. The Japanese still seem to maintain some sense of responsibility and lack the obvious cynicism and dishonesty newer Euro cars seem to be built around.

 

Quality parts for the 240 are getting harder to find. One of the things that led me to shy away from these cars (I used to have several but now have none) is that I was having trouble with rear caliper seizing. I would buy rebuilt calipers and in 2 years they would seize. I got tired of replacing them. I had a thread over on Brickboard discussing the merits of rebuilt calipers which concluded that the stock of good calipers is running out and even though they rebuild them and clean off all of the rust the start rusting again in no time. This may not be a problem if you don't live in the rust belt like I do.

I never had troubles with AMM though but I was careful to remove the thermostat in the air box so there was no chance of getting the hot air from the exhaust getting to the AMM. Over the years I had accumulated 2 good spare Bosch AMM I found in the junkyard. Basically if I was in a junkyard and ran across an AMM on either a 240 or 940 I would snag it as they would only charge me $35 for one. That was cheap enough for me to gamble on it. One of them I found there even still had a Volvo part number sticker on it. Unfortunately those parts went with my last 240 when I sold it a couple of years ago. The replacement car for that was a 2001 Toyota Camry.

 

I stay away from rust, I won't touch a car that has any signs of even surface rust. I don't know how people in rust zones deal with it. I see cars from the East Coast and after a couple of years they are visibly already affected... On the West Coast living by the beach is bad too, also to be avoided car wise. I never had Volvo rust issues-- they seem better than many other brands to fare well as they age. I enjoy my two Camrys now, I surprise myself as I never thought I would since I grew up with European cars in the '70s and '80s but what a sea change! I think BMW and Mercedes take the top prizes for worst reliability considering what they were. Audi were always shoddy but now at least they look good. VW is probably the only Euro car I'd have today if I had to choose. I have an '03 Passat 1.8T wagon 5 speed which is quite enjoyable but of course the model that succeeded it was crap. Why do they do that? It has to be by design. Sad new world we live in.

 

Thank you very much for your most helpful reply, Lev! As far as I know, my '82 245DL is not able to 'throw a code'. If it were, that might be helpful. An acquaintance, a very knowledgeable Volvo enthusiast, advised me that I could use the diagnostic procedures for my LH -2.0 AMM provided for '83 Volvos in the Bentley manual. If you know of a way to coax a code from my '82, I'd be very grateful if you revealed the secret! I'm grateful also for your report confessing your conversion from Toyota adversary to enthusiast! Following Pierce's tip, and the vehicle evaluations in the April issues of Consumer Reports and https://www.carcomplaints.com/, I have become a Toyota fan as well! My 3rd car was a used 1968 Saab Model 96 with a V - 4 engine and 42K on the odometer. After 37 years, and about 300K miles (twisted off 2 speedometer cables, so I'm not sure), I sold it for a dollar to an enthusiast (who invested heavily in its restoration) to spare myself shed tears on the way to the junk yard. The Saab front wheel-drive was absolutely trouble-free. By contrast, at 120K, I had to replace right and left drive axles, bearing hubs and ball joints on my '91 Olds Cutlass Calais! And the rivets that GM used to install the ball joints had to be drilled out after having removed the control arm! It is not just European cars that are money pits! Thank you again for your reply! I greatly appreciate your thoughtfulness!

 

Thank you very much for your reply, act! Being a rust belt inhabitant myself, I commiserate! My '82 was bought new in Colorado and given to me in 2005. I do not drive it in the winter to keep it out of the corrosive salt brine used on winter roads. Several years ago, I installed rebuilt calipers and have had no problems, Perhaps an application of silicon paste lube to caliper pistons would be helpful? I have treated rust vulnerable areas with oil or brushed on grease. I have also used 1/4" hardware cloth, wired onto an oiled rusted surface and coated with roofing cement to patch holes. A non-oil based paint can be applied to cured roofing cement. I'm very grateful for the caveat regarding the thermostat in the air box. I'll have to address that issue! Thank you very much for your thoughtful and helpful reply!

 

Living in Upstate NY most of my life, and only having owned used cars, I've been obliged to contend with rust as an inevitability. I have treated rust vulnerable surfaces with used motor oil, grease, roofing cement, caulking compound, 1/4" hardware cloth, roofing cement and paint. Having learned how to deal with rust, I am able to salvage used vehicles that are rust damaged and therefore much less desirable to most prospective buyers. I am expecting to replace my '91 Olds Cutlass Calais, that was given to me by an elderly neighbor in a very rusted and damaged condition a decade ago, with an older Toyota Corolla or Camry. The older models were smaller and had more road clearance on the front end. That is important for winter driving and negotiating steep driveway inclines. Thank you very much for sharing your most helpful thoughts!