My 98 Ford Ranger's radiator cap stopped sealing the other day. It ran hot and started backfiring while I was trying to make it home. After I let it sit long enough for it to cool, I figured out that it was the cap not sealing, so I replaced it.

Once I cranked it back up after putting more coolant in it, it still ran awful, spitting and sputtering and had very little power. Going down the road it wouldn't get over 30 MPH, still backfiring. I checked my plugs and changed the one fouled-out plug. I used blue devils head gasket sealer. I took it for a drive after the 50 mins and it's running a lot better but still backfiring. It's running kinda badly. What should I do? I'm stumped. I need some advice.


1 Answer 1


I would start by performing a compression test on each cylinder.

Overheating could have cause cylinder damage, or valve damage.

A DIY compression tester is not expensive and is generally easy to use, only requiring the removal of the spark plugs and disconnecting the ignition coils. It can also help identify if the cyclinder head gasket has blown between two cylinders which would show as low pressure on two cylinders next to each other.

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