How to check leak in the INTAKE

[mmguy]

We have a 1997 Jimmy with the 4.3.Have a coolant leak. Hoses are new and the thermastat.check for leaks everywhere found nothing.Floor boards are not wet and no antifreeze visable on the ground (looked quite bit over the last few weeks). Nothing in the oil.Truck doesn't run hot( runs about 195-200) you can smell antifreeze but not all the time.Right now will go thru a gallon of antifreeze every few weeks.So it has been suggested to check for a leak in the intake.
So ? is what can I check for? Is there a way for me to do a pressure test at home? Lastly changeing intake gasket is this a diffacult job?

[viggy58]

The 3 lower intakes i have done have all popped at the front of the motor. Behind, and just to the left of the AC compressor. Sometimes you see it pooling up right along the gasket. it usually burns off before it hits the ground.

Make sure your water pump isnt leaking. i have a small hose that has a drip that i just haven't gotten to yet.

The intake gasket could also be leaking into a cylinder. mine def was. one way to check is to remove your spark plugs. if one or more is completely clean, with no carbon buildup on it, you have coolant getting in there.

btw... whats your mileage? if your well over 100k and running the (orange) dexcool, you can prob bet that gasket is about to go anyways.

and replacing the lower intake gasket is not too difficult, especially if you have done any car work in the past. it also gives you an opportunity to clean up carbon deposits in the intake and throttle body

[gonzoblazer]

viggy is right. check your whole cooling system 1st, heat hoses,radiator,cap, upper-lower rad hoses, water pump,water pump in-outlet hoses. after all that checks out, there is a special tool you can hook up to the radiator. no idea on cost. i'm plumbing and heating so i had access to make my own. but viggy is also right about the spark plug check too. as for changing the intake gaskets, it is easy but give yourself time. it can be done in a day but i took 2 just so i wasn't rushed. i cleaned the snot out of everything i could get my hands on. there are very good DIY threads on this forum for changing your intake gaskets(i think the guy that posted it had a red 97 jimmy too).

[MT-2500]

They make coolant dye to put in coolant for hard to find leaks.
Add some to coolant.
With a hand held pressure tester on coolant system.
Pressure test cold and warm and hot.
And look for leaks.

[mmguy]

Thanks everyone for the advice.To answer some of your ?'s.
It is a 1997 and has 136,000 miles on it and does run on Dex-cool.I replaced both hoses the rad cap and the thermastat about 3months ago.Truck doesn't seem to run any different just the coolant loss.

Thanks

[MT-2500]

You are welcome.

Many places can make it lose coolant.
Time for a coolant system pressure leak test to find the right spot.
Let us know what you find.
And be sure to watch the oil for coolant in it.
Good luck