Hello All,

At 430,000 miles, my red 1996 850 GLT wagon naturally aspirated, with a 5-speed manual has suffered a burnt valve in cylinder #1. I will probably do the insane thing and have it fixed, which per my mechanic means removing the head, and replacing all the valves and sending the head out to be machined. The estimated cost will be $2,800 on a car that probably has a value of $1,000 to $1,500. That car is very well maintained both inside and out and is belies its age and mileage. This was the first Volvo I ever purchased and I purchased it new
back on April 12, 1996.

Throughout its life, I have run it on 87 octane with no noticeable adverse reaction. After the valve job is done, should I continue using 87 grade octane or switch up to 91 grade. The owner's manual does recommend 91 grade, but I am a cheapskate. At 430,000 miles, I can't say for sure whether it was 87 grade gasoline or the 430,000 miles that did in the valve (maybe both).

I welcome all suggestions and comments.

Hugh

I have used Susoco 260 for all my machines since we took a trip from Massachusetts to Foam Lakes Saskatchewan to visit our wild life biologist daughter. 4990 miles in 9 days in our 745.

I always write the mileage on all our gasoline purchase a slips. That way I can check gas mileage on a trip.

One stop in Quebec, I put the cheapest level of octane in by mistake (French gas pump). My gas mileage was 4 MPG lower for that tank!

Everyone thinks that the knock sensor will accommodate low octane. You know what the computer does when the engine knocks? It adds a lot of extra fuel to cool the cylinders. Changing the timing does not work because the engine if already firing before the plugs spark! Eventually it adjusts the timing.

I have never found a good explanation of exactly happens with a knock, but I have read about the extra fuel addition.

I would suspect a bad injector before I blamed low octane on an engine that old.

Make sure you read my other post before you spend money or energy.

I often keep my cars too long - I had to sell out '90 744 TI for $500 after putting that much on the car in new tires. My wife would not drive this beautiful car with no AC!

You did get your monies worth! Swapping in a newer engine may be much better than rebuilding this one. I would be skeptical about an engine with 52K miles. Has it been sitting around getting rusty for 25 years?

As for 87 Vs 91, seems like the 87 was pretty good.
--
Keeping it running is better than buying new

Klaus,

Thank you for your compliment about getting my money's worth out of the red 850, and "Thank You" to those who responded above your reply. By the way, you were right to be skeptical about the engine with less than 52K miles (51,975). That was the accurate mileage on the car, BACK IN 2011 when the odometer broke. CarFax revealed that information and the fact the Volvo was totaled in a head on collision in September of 2011, where the odometer still read 51,975.

Hugh

When crunching the numbers to decide whether to re-engine it or dump it don’t forget that you would likely want to replace the clutch, new rear main seal, some new hoses, belts (timing belt is likely 10+ years old), new motor mounts, and …… well, I think you get the picture.

Then on the other hand, a nice 850 with a manual can be a desirable car. Plus I’m hearing all about how car values are currently swayed in sellers favor right now, making a replacement car more expensive. Not sure if that is really the situation or not.

Chris,

I just read the other day the average price of new car purchase is over $42,000. I can only imagine where the new Volvos land on that price curve. Thank you for reminding me of the ancillary expenses that will be incurred with either an engine swap or rebuilt, that will add to the total cost.

Hugh

It looks like you want to keep putting money in the 850 because you love it. If you do the work run 91. Better gas milage and power, plus you should get another 500k miles out of her. I'm thinking of retiring my 1993 850. Just tired of always fixing something. Had it since new but over it, I think.

David,

I do have a special place in my heart for this car. I still haven't made up my mind, but if I fix it, I think I will treat to 91 for the rest of its life. Thank you for your response.

Hugh

David,

You are right. I do "Love" this Volvo and that is the problem. This was the first Volvo my wife and I purchased new shortly after we got married. My youngest daughter, age 21 currently drives it at college in VA. I let her take it because I knew none of her friends would borrow it because it was a manual. There is another issue: the piston rings are worn. When you accelerate from a stop, blue smoke can be seen from the exhaust. It goes away once the engine hits cruising speed. My mechanic said it would make sense to address that issue at the same time the valves are fixed, but it would be additional money. Meanwhile since I posted the query above, I have located a used motor out of a 1997 850 with just under 52,000 miles that can be shipped to CT for $1,100. I don't know how much the cost to install it would be. I would bother too the car no longer had the original engine, but installing a used one may be the way to go. Of course, dumping even that kind of money into a 25 year old Volvo with 430,000 miles, doesn't make sense economically.

Thank you for sharing your thoughts about 91 vs 87 octane. I hope I make the right decision. We don't last forever, and neither do Volvos. But still....

Hugh

Hugh,

Agreed, it doesn't make economic sense to put that kind of money into your car. I do understand you love the car but try not to let your emotions rule in this situation. IMO - If you decide to move forward, the used engine makes the most sense. Do get a price for installation first. Doing a valve job on such a high mileage engine is a bad idea. It will wear the bottom end of the engine out faster. Since your piston rings are leaking anyway personally I would stay away from that option. If you buy the engine will it come with a warranty? Make sure it does. A 52k engine sounds like your best option if you decide to keep the car.

Jim
--
Will I buy another Volvo??? We'll see....

Hugh,

Agreed, it doesn't make economic sense to put that kind of money into your car. I do understand you love the car but try not to let your emotions rule in this situation. IMO - If you decide to move forward, the used engine makes the most sense. Do get a price for installation first. Doing a valve job on such a high mileage engine is a bad idea. It will wear the bottom end of the engine out faster. Since your piston rings are leaking anyway personally I would stay away from that option. If you buy the engine will it come with a warranty? Make sure it does. A 52k engine sounds like your best option if you decide to keep the car.

Jim
--
Will I buy another Volvo??? We'll see....

Jim,

Thank you for your dispassionate advice. I'm still on the fence about what I will do. Your advice and the others I have received are helping me to make the "right" decision. I wish I was a millionaire, and could just write a check and yawn in indiffernce.

Hugh