Hey Guys, this is my first time here so be gentle. I have recently purchased an 87 Accord with 125k on it. Here's the problem. At interstate speeds (75-80mph) it starts trying to run hot. I can also make it run hot by running at higher RPM's in a lower gear. Around 3,000 rpm's seems to be where the trouble starts. I changed the thermastat and it didn't help. I was going to go ahead and replace the water pump but it appears to be new or recenlty replaced. I know on older cars you can squeeze the top radiator hose to feel the water circulating therefore ruling out the water pump, does that work on these cars? Thanks for the help in advance.

 

First thing is to be sure the block is burped via the 12m bleed screw at the T-stat housing. Be sure the cooling fans are cycling. I've seen cast impeller water pumps run at higher temp than the OEM vane pump. You could start the car from a cold condition, then feel the temp difference between the top and bottom radiator hoses. The top hose will get hot first then the bottom hose. Your description of the problem sounds like a plugged up radiator.

 

Honestly it sounds like your radiator. Honda radiators are made of plastic and thus over time can crack which can result in overheating in many cases. If it is your radiator don't, and I repeat, don't buy one from an auto shop. Right now on Ebay there are a couple of radiators for around a hundred bucks. Mine started the same way with the overheating at the upper RPMs. Any auto shop should have computer that can hook up to your car and tell you exactly where the problem is (usually around 30 bucks).