I have a 403 in my cutlass. Ive had the car for almost a year and driven it around 2000 miles. It is a recent rebuild (approx 20,000 mi), and it has always run pretty cool (around 175-190 even on a hot day). Recently as I was driving home from school, it started pinging real bad and the temp went up to around 225. Any ideas on what might have happened all of a sudden? Thermostat maybe? Thanks in advance for any help.

 

Thermostat could be stuck but if you installed a new one when the engine was rebulit can't
see it failing that fast.Those cars had a EGR valve and when they don't work properly you can get pinging at partial throttle .How detailed was the rebuild ,like everything new or was there parts reused?If you want to check the thermostat you could remove it and test it in a pot of hot water with a temp gauge and see when it opens ,or just put in a new one,
get a fail safe one ,that stays open when it fails so coolant can still circulate.

 

It had a complete rebuild and everything was brand new so it could just be a defective thermostat. The same overheating problem happened to my 70,000 mile 2000 grand cherokee last year and it was the fan clutch. Could I be having a fan clutch issue with the cutlass? I want to be absoulutely sure before I spend any money on parts to fix it, because Im a full time student and my money is pretty tight right now and I dont want to buy parts that I dont need. Thanks for your help.

 

Sure, it could be the fan clutch. That's what it ended up being on my car when my engine was running hotter than I wanted it too ( though never came close to overheating ). To test it, just give the fan a spin with your hand. If it's tight and only turns a little then quickly stops, it's good. If it seems loose and spins around too easily like it's 'freewheeling', it's bad. Also check to see if it's leaking.

Just a note on that; when I suspected a bad fan clutch on my car and I checked it by spinning it, it was tight, so I figured the fan clutch was good. I was wrong. The fan clutch was bad. On mine, when I checked it ( and I did multiple times ), the engine was always stone cold. My clutch grabbed very good when it was cold but when I finally checked it one day after the engine was warmed up, it freewheeled pretty good indicated it the clutch was shot.

 

Is it low on coolant?

 

Found out it was overheating due to low coolant and the coolant was low beacause the heater core just sprung a leak. Its all over the carpet now. How to I get to the heater core to replace it? Under the hood or under the dash? Ive heard these are a pain in the a$$ to get out, is there any simple way to make this repair?

 

By pass the heater core until you can afford to fix it properly because i do believe you have to get it out from inside .You probably won't need much heat coming into spring anyways.

 

maybe like this idea

 

Or you could just connect the hose from the water pump to the rear of the intake manifold.

 

What year Cutlass? Glad it was an oblivious problem.

 

Same thing....and I agree. Bypass the heater core until you can figure it out/afford to fix. Depends on the year of the car as to whether you can get to it from the inside or engine compartment (71-72 are under dash).
Good luck!

 

Thats exactly what I did. My friend told me that the heater core is accesible from under the hood. Is that true?

 

It a 69. Its nice that the problem was obvious, but now I have to take out the carpet and clean or replace it. Over two gallons of antifreeze soaked into it.

 

Much easier if it doesn't have a/c.

 

My 2 cents...Suck up the coolant from the carpet with a wet n dry vac so its doesn't rot the floor. Use plenty of water while doing this so you aren't stuck with a dry but sticky carpet. The jute pad under the carpet will take days to dry. Better yet Id just remove the carpet from the car hose it down, let it drip dry, suck it as dry as possible with shop vac then let it hang inside for a week. Remove the seats. Seat removal will also allow easier clean up and access under the dash.
Nows also a great opportunity to flush the cooling system. Do not use tap water to mix coolant when refilling. I buy the pre-mixed 50/50.
Stant makes a higher quality HD T-stat for a few dollars more than the standard unit. Well worth the extra $5. Dont forget to inspect all hoses. Replace them while the systems down for many worry free miles.