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Coolant leak from under intake manifold, rear passenger side?
Hello all, got another question sprouting from my 98 GT. I spent the last two weeks installing an ac bypass pulley, idler pulley, belt tensioner, and belt. Before I started the work, I noticed some moisture od some sort at the top back corner of the engine, passenger side, near the last spark plug wire. I thought it might be oil leaking from my head cover gaskets again but figured I'd wipe it up and tackle it after I start the engine again.
Fast forward to tonight, I finally started up the engine and let it run for about 5 minutes to make sure all the belt stuff looked and sounded ok (it does at the moment). When I checked that back passenger corner again, I saw a small collection of green coolant. Looking under the car, there a small puddle of coolant on the floor under the rear of the engine.
Where can I begin investigating to find where this leak is coming from? A quick internet search suggested the heater hoses but if that's the two hoses above the engine by the firewall, those are showing no signs of coolant leaking at all. Anywhere else?
I bought this car to learn how to do my own maintenance but it's been forcing me to learn a bit faster (and pricier) than planned.
My 02 had a leak in one of those hoses. It was a very small leak. Sorry I can't be of much more help.
Hey now, dying apologize for trying to help, I appreciate it.
I decided to clean off what coolant I saw and try starting the car up again. Let it run long enough to turn on the radiator fan and sure enough, no sign of leaking. Guess I'll just have to keep an eye out for it.
After running the mustang some more, I didn't notice any more leaks but I did notice a faint smell of coolant when I'd park the car.... That is until I parked the car on my inclined driveway and noticed a consistent small wet trail in the driveway under the car going from below the rear of the engine bay and down to about half the length of the car before evaporating I suppose. Also it does look like potentially some moisture in the valley under the intake manifold but not a puddle/pool.
Opening the hood, I definitely see coolant on the rear passenger side of the engine where the intake manifold and block meet. As coolant loss seems to be very slow and there's no white smoke out the exhaust, I'm crossing my fingers that it might just be a leaking intake manifold gasket.
However, if it turns out to be a crack in the intake manifold (knock on wood), what should I do? My next large goal for the car was to either swap in a newer PI engine or have the engine rebuilt (it has 180k miles on it) and install the PI upgrades, ultimate goal being a supercharger many many many years from now.
If I were to replace the intake manifold, I'm tempted to get a cheap one as a temporary fix but seeing as how the ford racing PI manifold is $250+, should I just aim for a newer engine altogether? I don't want to keep throwing parts at this old oil covered engine if it keeps popping up with new issues as soon as I fix one.
I got the car to learn car maintenance but I also need to think of cost effectiveness (for the family budget sake).
Last edited by Longtermmustang; 06-06-2019 at 04:24 AM.
Pressure test the cooling system when cold if you want to more easily see where leaks are coming from. At room temp all components are shrunk. When pressurized, fluids will more easily flow out of a leaky area vs when things are hot and expanded.
Pressure test the cooling system when cold if you want to more easily see where leaks are coming from. At room temp all components are shrunk. When pressurized, fluids will more easily flow out of a leaky area vs when things are hot and expanded.
I took your advice and rented a coolant pressure testing kit. Pumped it up to 15 psi and immediately noticed a tiny drip from the underside of the reservoir, dripping from the top large hose (tightenrd the clamp and it stopped), a dribble from the passenger rear corner where the intake manifold and block meet, and a tiny leak from the front passenger corner of the intake manifold/block intersection (the aluminum crossover looked to not be leaking at least). Also lost 1 psi in less than 15 minutes before I stopped inspecting and released the pressure.
So yup, guess I'll start with a new intake manifold gasket? And check out the reservoir and hose. Parts parts parts lol.
04-08-2019, 12:50 AM
Coolant leak from under intake manifold, rear passenger side?
