K-Car, overheated, backfiring through carburetor
#1
06-19-2007, 10:28 PM
K-Car, overheated, backfiring through carburetor
I had my thread all typed, and while I was previewing it, hit the wrong tab and deleted the whole thing! [:@][:@][:@]
Over a year ago, I overheated my Mom's '83 Reliant (2.2 engine, 85,000 miles) when I left it idling in the garage (50 degree day, door open). The coolant had boiled the overflow tank full, with some spilling onto the floor. The engine was still running, and I shut it off and briefly restarted it. It made some sort of noise that I thought was a knock, so I quickly shut it off. A week later, I came back and refilled the radiator and started the car. It immediately started leaking coolant from the heater valve near the firewall, so I shut it off. Because my mom can no longer drive, we just let the car sit for over a year. Now, my sister wants to have it available for when she and her husband fly up for a visit.
Recently, we replaced the water valve andfilled the radiator with water. We thenpoured a little gas down the carburetor, and it started without too much difficulty, but it backfired through the carburetor with a sharp, staccato sound. It did fast idle by itself and the backfiring seemed to decrease, but never go away completely. My guess is that the sound is caused by the intake valves sticking; sound right? We left the radiator cap off and let it idle for 3-4 minutes. The water got hot enough to burn my finger and put out some steam (water vapor) into the air. I did see some tiny bubbles in the coolant, but nothing like when my diesel Rabbit blew a head gasket. I didn't see any flow of coolant, so either the thermostat had not yet opened, or else the water pump was not working (see next paragraph).
My BIL was convinced that the water pump was bad, so he bought a new one. We removed the old one ( a lot more work than I thought it was going to be), but when I split the old one to install the new half of the pump, it seemed ok. I haven't had time to install it yet, but thought I would replace the timing belt while everything is off. Does anyone think that the timing belt might have jumped time?
I plan to put everything back together and add some Marvel Mystery Oil in the hopes that it will free up the valves. If that doesn't work, I might pull the head and have the valves redone. If the head is warped, we will have to evaluate whether it would be worth the expense to replace it. We don't want to put too much money into it, as it would just have occasional use. Any ideas on how much a rebuilt head would cost?
Any comments, suggestions?
TIA, Brady
Over a year ago, I overheated my Mom's '83 Reliant (2.2 engine, 85,000 miles) when I left it idling in the garage (50 degree day, door open). The coolant had boiled the overflow tank full, with some spilling onto the floor. The engine was still running, and I shut it off and briefly restarted it. It made some sort of noise that I thought was a knock, so I quickly shut it off. A week later, I came back and refilled the radiator and started the car. It immediately started leaking coolant from the heater valve near the firewall, so I shut it off. Because my mom can no longer drive, we just let the car sit for over a year. Now, my sister wants to have it available for when she and her husband fly up for a visit.
Recently, we replaced the water valve andfilled the radiator with water. We thenpoured a little gas down the carburetor, and it started without too much difficulty, but it backfired through the carburetor with a sharp, staccato sound. It did fast idle by itself and the backfiring seemed to decrease, but never go away completely. My guess is that the sound is caused by the intake valves sticking; sound right? We left the radiator cap off and let it idle for 3-4 minutes. The water got hot enough to burn my finger and put out some steam (water vapor) into the air. I did see some tiny bubbles in the coolant, but nothing like when my diesel Rabbit blew a head gasket. I didn't see any flow of coolant, so either the thermostat had not yet opened, or else the water pump was not working (see next paragraph).
My BIL was convinced that the water pump was bad, so he bought a new one. We removed the old one ( a lot more work than I thought it was going to be), but when I split the old one to install the new half of the pump, it seemed ok. I haven't had time to install it yet, but thought I would replace the timing belt while everything is off. Does anyone think that the timing belt might have jumped time?
I plan to put everything back together and add some Marvel Mystery Oil in the hopes that it will free up the valves. If that doesn't work, I might pull the head and have the valves redone. If the head is warped, we will have to evaluate whether it would be worth the expense to replace it. We don't want to put too much money into it, as it would just have occasional use. Any ideas on how much a rebuilt head would cost?
Any comments, suggestions?
TIA, Brady
#2
06-20-2007, 04:34 PM
#3
06-20-2007, 05:11 PM
RE: K-Car, overheated, backfiring through carburetor
Backfiring could be caused by timing that is extremely off.
A rebuilt head could run you anywhere from $50-$250 or more, depending on where you get it from. You could check local scrapyards for a cheap one, but it might not be much better than the one you already have...
Beyond that, I have no idea. I've never worked on the carb'd engines...
A rebuilt head could run you anywhere from $50-$250 or more, depending on where you get it from. You could check local scrapyards for a cheap one, but it might not be much better than the one you already have...
Beyond that, I have no idea. I've never worked on the carb'd engines...
#4
07-02-2007, 02:15 AM
RE: K-Car, overheated, backfiring through carburetor
Dusty: Thanks for the response. I thought I would have more to report back to you,but have been making slow progress. I did determine that the fan was not working, so that might have been the reason that it overheated. The fan motor tested good, so I am hoping that replacing the fan switch will fix that part of the problem. My Haynes book is not very clear on what else might be the problem.
I substituted a quart of Marvel Mystery Oil for one quart of oil, and ran the engine briefly, until it heated up. It seemed to smooth out a little, but there is still a consistent backfire from at least one cylinder. I also dribbled in a little bit of Sea Foam through the carburetor while the engine was running, but had to quit before getting much in because of the fan problem. I'm hoping that it will eventually smooth out enough to be drivable.
I will report back with any progress and maybe more questions.
Brady
I substituted a quart of Marvel Mystery Oil for one quart of oil, and ran the engine briefly, until it heated up. It seemed to smooth out a little, but there is still a consistent backfire from at least one cylinder. I also dribbled in a little bit of Sea Foam through the carburetor while the engine was running, but had to quit before getting much in because of the fan problem. I'm hoping that it will eventually smooth out enough to be drivable.
I will report back with any progress and maybe more questions.
Brady
