302Travis

Hi I have a 2000 gt, and about every 800 or so miles or about every month is seems to lose about 10 ounces or so of coolant. Hadnt found any leaks and never smell anything. Suggestions?

Barrelroll706

Make sure you check that you don't have coolant in your oil. Last time that happened to me was in an old 94 pontiac...and it turned out the coolant was leaking into my oil

Dragonus18

+1 on that. My car has been in the shop for 3 months because of the same problem.

302Travis

No indications there is any in the oil. From checking it to changing the oil it seems fine. Ive been wondering if the intake gasket is leaking a little in. Possible?

Soldier GT

Man, if I were you I would stop guessing on this. I would probably take it to A reputable mechanic or at last choice, the stealership and have it checked out. GL!

302Travis

'Stealership'. I like that! Na, I prefer to do it all myself (it's cheaper, plus I know the condition of everything as I tear into it). Just my preference. The only thing is I don't know of any way to tell if what I believe is happening is happening without taking the manifold off.

And as long as it loses coolant at such a slow rate, I'm not entirely that worried about it. My 93 f150 has always slowly lost some at about the same rate with no issues other than needing a quart or so of coolant at about every 1500 miles.

I'm trying to see if it is a common problem for these 4.6's mostly. I've owned the car for about 6 months and that's it. Nice 03' btw

Stevo86

No, it is not a common problem and is in no way a normal occurrence. The cooling system should be a 100% sealed system in order to function properly since natural pressurization of the coolant is part of how it works.

Your should go to you local auto parts store to rent a cooling system pressure tester. Use it to pressurize the system to a PSI or so below whatever is listed on your reservoir cap. The system should hold pressure, if not then you have a leak and you can start to narrow it down. Under 15 or so PSI any leak should make an audible hiss and you may see the coolant coming out.

If you still can't see anything it may be leaking into the intake or the cylinders. You can pull the spark plugs to check the cylinders. If they're all dry and you still can't see it the problem is most likely the intake gasket. Unless of course you forgot to mention something like foggy windows when you turn on the heat. Good luck

petrock

+1 on the pressure tester. Do it with the motor cold and with the motor warm (not hot). Some leaks only materialize with the motor warmed up due to metal expansion. Be careful not to scold yourself with boiling hot coolant though. Run the motor to operating temp with the radiator cap off. Make sure to have a catch can or tray or ‘no spill’ funnel ontop of the radiator when you do this. It can get messy.

I had a similar problem on my wifey’s ’98 3.8L. Turned out to be two leaking freeze plugs. One was behind a motor mount too. Ended up pulling the motor entirely, replacing all the freeze plugs and a bunch of leaky gaskets. Been running like a top ever since.

Here is the funnel I’m talking about, btw: . Its great for refilling & burping cooling systems too.

Good luck...

school boy

He needs to leave the cap on so the coolent system is pressurized, otherwise it might not leak.

Stevo86

Yeah if you wanna heat it up just hook up the pressure tester and then start the car. It's not gonna hurt the tool and you will be able to see what kind of operating pressure your system is under.