camarols62002

I have an 2002 z28 i bought a month ago that has 105k on it... lately i have noticed that my coolant hoses have alot of pressure when its hot... like it feels like its going to pop... it keeps blowing coolant past the clamps on the bottom hose. ive changed the t-stat, rad cap and lower hose with two new clamps and it still does it. the heat works fine and it doesnt over heat. there is no coolant in the oil and it doesnt blow steam or smoke out of exhaust. any ideas?

NBM99SS

iTrader: (33)

Fans comming on? Sure you have good flow through the radiator?

camarols62002

yea the fans are coming on... both upper and lower hoses are hot so im guessing im getting good flow... i did notice when i turn the heat on the pressure drops a little bit. maybe a radiator?

doublea87

iTrader: (16)

have you checked pressure going in and out of the heater core? might be possible that the core is getting clogged and the pressure is building up through the water pump and into the hoses. however you did say you got good heat so yea.. thinking out loud lol

camarols62002

every single hose in the system feels like it has the same pressure.. i am so stumped

mattmatt350

that is confusing but do the hoses become soft when cool? Since you said you replaced those parts and that didn't fix the problem I would say your radiator is clogged but if it was your lower hose would have less pressure than the upper but not by much (or vise versa). the other thing is what color is the coolant? GM cars need the "red stuff" and if your car has the "green stuff" or a mixture of the two, you have a cause for corrosion and need to flush the system.

camarols62002

it seems like the bottom hose it getting it worse because its the only one wanting to let go... i only use dex cool... if i can get a radiator cheap enough i might throw one in to see what it does... i am all out of ideas and i really dont think its the head gaskets.

JaYZeig

iTrader: (11)

id maybe try runnin it with the radiator cap off to see if coolant blows out of the radiator neck..good sign you possibly have a failed internal head gasket leak. theres also kits you can buy that will go on-top of your radiator inlet where the cap goes on to detect combustion chamber gases in the cooling system.

wssix99

iTrader: (5)

Correct. Its a pressurized cooling system and is designed to be that way. The radiator cap controls the pressure and relieves any excess that is building up. Since you've already changed it, you should be correct with regard to pressure.

If your cap is the correct one and your new lower hose is the correct one, you may check the barb for the hose. The clamp requires a properly formed barb to work.


Can you post pics and the part numbers of the parts you installed? If everything is tight, you might have a blown head gasket. (That would create overpressure faster than your radiator cap could bleed it off.) My understanding is that a coolant pressure test can confirm this.

camarols62002

nothing is bubbling with the cap off. i pulled the plugs earlier and they are all fine. Friday i am going to do a hydrocarbon test and see what it tells me

wssix99

iTrader: (5)

You could also use a pressure test to confirm if the hose/radiator connection can hold up to proper/normal pressure.

LS6427

iTrader: (2)

Only way a cooling system can get OVER-pressurized is from air entering the system via a blown head gasket(s) or when coolant slowly leaks out of a system and it reaches a point where the void gets so large that you will over-pressurize.

But in both cases the coolant will exit through the radiator cap, into the over-flow tank and it will ultimately boil over out of the over-flow tank cap....

You may be worrying about nothing, as those hoses should be pretty friggin hard and plump when the engine is at normal operating temp. Mine are very firm.
Or possibly a tiny blown head gasket letting very little air into the cooling system and you have the wrong radiator cap (18psi is normal) and its holding that pressure. ((doubt this is the issue))

Putting the heat on should change the pressure in the system because it drops temps pretty good, and pretty fast too.

If you're not overheating and you have the correct 18psi radiator cap.....and you say you have flow when the radiator cap is off meaning you also have all the air out of the system.....

I think you're just fine.

Radiator and heater core "clogs" are almost non-existant, you would almost have to drop something into your radiator to get a clogged condition......there's nothing in the entire system that can break free and clog the system either. Unless your Dex is 14 years olf and one of the bad engines that gets real bad gunked up Dex.....thats not the clog either.

Also, I hope you're not running 100% Dex....thats just wrong.

I'd say nothing is wrong with if your temps are normal.

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