vanfossenkelly

Ok I have a 94 z28 with what I believe to be a 97 z28 engine. I figure this because the radiator is from a 97 and all hoses connect perfectly where as on a 94 radiator there Is missing spouts on the radiator for all my hoses. Anyways my problem is with everything connected my car it will heat up to 235 degrees never above that then slowly drop back down to 185 and slowly work its way back up again slowly fluctuating constantly while driving. And my radiator hose with the thermostat in It will swell and turn my low coolant light off. Now the strange thing is once I unplug my mass air flow sensor the car drops to 180 degrees instantly and the swelling immediately goes away in the hose and stays that way even after an hour of idling and driving. Then once plugged back in it will gradually work its way back up in degrees and do this all over again. Yes my system is bled properly. Cause if it werent plugging the mass air flow sensor wouldn't matter it would still fluctuate and it doesnt move at all from 180 degrees with the sensor unplugged. Has any one else had this problem or have an idea what it is?

garygnu

you engine temp sensor probably is bad.your fans mite not be running to cool the engine.

LopeyZ

iTrader: (2)

I can't imagine how the MAF sensor could have any effect on engine cooling. And I'm not aware there are any differences from a 94 to 97 radiator. I think you need a good system flush.

vanfossenkelly

Fans are working like they should no problem there. And ya I can't figure out why the maf sensor would effect the temp either. It's throwing me off extremely. I just put in a 180 thermostat today and it gets up to 220 then cools back down to 190 almost instantly then slowly climbs back up to 220 but isn't hitting that 235 mark anymore

SS RRR

iTrader: (2)

Other than low coolant and a weak hose, I don't see a problem with the coolant temps unless your fans have been tuned to come on earlier and running a 160 thermostat.

vanfossenkelly

It's all stock. Running a 180 thermostat and normal fan programing. So your saying its normal for my car to run up to 225 then fall back down to 190 and keep doing this the entire time I'm driving? Just seems weird to me is all. Cars generally should sit at a constant temp. And I know that direct from the dealership they did sit at a constant temp with no major fluctuation. Currently I have replaced hose and new 180 thermostat. Hose no longer swells but is still doing all the fluctuation with the temp

SPF77

It wouldn't hurt to change your coolant temp sensor and flush the system. The only time my temperature fluctuates like that is going from highway driving to city driving, but my temp always stays below 210, even sitting in traffic. It may be a pain but knocking our a freeze plug might be a good idea to see if you've got a lot of solid matter in the cooling system. I've had that problem before.

vanfossenkelly

Just thought of this as well, car is missing the lower air damn and radiator cover. I know this can drastically help with cooling but doesn't cause fluctuation however it may cool off me engine enough to where the fluctuation will be of less higher degrees... Yes, no? It's just a thought. What do you think

BOOSTED AFR

Definitely need those pieces for proper operation of the cooling system, run it as GM designed it and you should be ok. However I agree that those probably would not cause a fluctuation.

93 LT1 Vette

Sounds like you have some air pockets in your cooling system. Service it, start it bleed off the air at the bleed screws on the T-stat housing. Service it bleed it until nothing but coolant comes out of bleed screws. Don't get the opti wet!

vanfossenkelly

Ya as stated in first post it Is bled. Strong solid stream of only coolant coming out of both bleeder screws.

englundjd

These cars operate like that from the factory. The stock fan settings on a 94 are set to come on at 235 or so. You need to get an air damn and a radiator cover... There important to the cooling system

The reason the car runs cooler with the maf unplugged is cause if the car is throwing a code it turns the fans on and keeps them on as a precaution

Tolley's94z28

iTrader: (4)

You would be surprised how weird these cars can act if the air dam is missing. A few summers ago I took mine for whatever reason(can't really remember) and it ran hotter than usual and fluctuated too depending on speed, day temp., and things like that. I put it back on and never had any more problems.

Try that before going and spending money on sensors and hoses.

vanfossenkelly

Ya im definitely gonna do that. I already replaced the hose only because it was expanding it was obviously weak so I went a head and got a new one. However I cannot find a radiator cover and air dam anywhere. Was gonna make my own but would really rather have the factory ones.

Big Al

iTrader: (1)

I know you said the cooling system is full, but it still sounds like there is air in the system to me.

Al 95 Z28

ss1129

iTrader: (16)

What he said. Mine was just loose and kind of flopping / swaying and it was reaking havoc on me. I tightened it up and it solved everything.

vanfossenkelly

Ya I agree I'm definitely taking on air into my system somewhere its the only cause of fluctuation in any car. I'm gonna remove my whole cooling system and rebuild it. Im sure as I'm breaking it all down I will find where it Is. So just a final question since the only time it stays cool is with the mass air flow sensor unplugged and yes I know it goes Into speed density mode but it does keep my fans on and keeps my car at normal operating temp will It really cause any damage to do this just so I don't warp a head until I an tear it all down. And i cant afford to do the manual fan set up yet so my only option Is to run with the maf unplugged. But will it cause any damage? I plan on leaving the whole intake still on and just unplug it

BOOSTED AFR

Most likely it will set a code for MAF failure or not present, but the car will operate and drive just fine with no adverse effects.

vanfossenkelly

Ya I'm not really worried about it throwing a code since I know what it Is. Just wanted to make sure it won't screw up anything else on my car ya know? Also in your opinion should I leave the full intake system on or run It with the intake completely off and just an open throttle body

BOOSTED AFR

Leave the intake on it. You really don't want to suck up a rock or dirt or anything. It wouldn't take much to really put a hurt on the motor.