jonalman

hi, i have a 93 mustang,and i am having a problem with my 347 overheating. the engine is naturally aspirated. i originally thought it might be a sticky thermostat, so i bought a high quality one, and swapped it out. (and its in the right way). but i have no idea why my car is overheating... all of my fluid levels are full, and i bought a new radiator cap thinking the system wasn't pressurized, or something. and that did not work.. i will be driving around and the temp gauge will stay at about 170 or 180ish, and then all of a sudden, the gauge shoots up to 250 and sometimes pegs out... does anyone have any ideas?

saleenpride1986

When you warm up your car (not super hot but just warmed up enough so that the radiator would work it's magic) feel the upper and lower radiator hoses, make sure they are both warm. If one is cold and the other is hot, could mean radiator needs a flushing. OR if they are both warm then you have proper coolant on that end meaning it could be something else in the engine. If both hoses are cold, then it's likely the thermostat and i'd re install the new one you just bought.

stanglx2002

Check the temperture of the fluid in the radiator when the temp spikes because it could just be the temp sender

white93pony

sender could be bad

Timspony

Could be many things: air pocket, radiator, water pump, thermostat or sensor...maybe even a blown headgasket...start by checking fluid levels and as described ^^^ & also check the hoses once up to temp....

MBDiagMan

Start by pressure testing the cooling system and the radiator cap. Most radiator shops will do this for free.

cch

Could be that you have an inadequate water pump; not enough flow.

ponyponer

yeah a similar thing happened with my water pump on my 5.0. the bearings were making a bunch of noise, and it did not appear to lose any fluid. still it was getting hot. i'm the king of procrastination so i didn't take care of it right away. the next week the seal popped, and started leaking too. and it wasn't leaking too much or at least not enough to compensate for how hot it was getting. it was some internal water pump problems causing most of it. by the way that picture in your signature with the church, and the saying about the civic is awesome. it's hilarious!

Portmaster

The way the gauge pegs out so fast it sounds as though the the sending unit could be going south. Check the wiring out going to the temp sensor and make sure it's not grounded.

cch

Thanks bud, ya was hoping I could give a few laughs with it. But back to the water pump; I had the stock one on my 302 and started noticing that the engine was getting hot. That's when I noticed that I had a slight leak at the pump. Anyhow, about a week later I had my new Meziere electric pump in the passenger seat and going up the drive way to the shed to install it when the mechanical pump blew. Prestone everywhere! Anyhow, it only took an hour and the problem was fixed. But to anyone out there I highly recommend the electric pump. I have mine in chrome so it looks awesome, plus when I decide (ie: scrape the money together), to get a crate engine it can just be switched over. Just a story for y'all I guess.