2001 L300 Coolant leak - HELP!

Old 07-17-2015, 04:58 AM
Thread Starter
Join Date: Jul 2015
Posts: 3
Question 2001 L300 Coolant leak - HELP!

So, wife tells me the light is on. Open hood and reservoir tank is empty. Start to add coolant/water (engine off) and engine starts leaking, reservoir tank empties totally. Coming from under intake manifolds, not seeping, pouring out. Sigh. Pull the manifolds (upper and lower), fuel rail, injectors, spacer block. Plug the gaping holes to keep clean. Add fuid to reservoir. Not leaking from thermo housing or oil cooler cover, my first two thoughts. It's shooting out of a small hole on the top of the engine block (a manufactured hole, looks like a weeper/breather/overflow, about 1mm round) on the block between the thermo cover and oil cooler cover. It's shooting out, driven by pressure from elevated reservoir tank.

No milkshake, oil and coolant dirty but clear (thank god maybe). No dexcool buildup or residue on timing cover, I have not pulled this yet to inspect/get to water pump coz that's painful. Pulled the thermo housing, thermo tight in closed position but replacing that anyway for the 20 bucks. Ordered and waiting on thermo, gasket, spacer block gaskets and injector gaskets.

What is that hole? I cannot find it on any engine schematics or L300 service manual diagrams, no reference to it. Without pulling the oil cooler cover (also a pain), I would guess that hole leads into the coolant channel that the oil cooler is bathed in, between the oil cooler well and t-stat. So I'm thinking...if the coolant is a pressurized system, and coolant is blowing out with just the head of the elevated reservoir tank, wouldn't it blow out under pressure regardless?

Thinking I'll try a back flush, maybe something is clogged. Maybe water pump is shot with fins blocking the flow creating the clog and so fluid is backing up and coming out of this hole.

Any thoughts? I'm scratching my head here.
Old 07-17-2015, 06:32 AM
Rubehayseed's Avatar
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Join Date: Jul 2011
Location: Lake Wales, FL
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I wish I could help you, man. But I know absolutely nothing about the Saturn V-6. I've never owned one.
Old 07-17-2015, 08:56 PM
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Snappy little engine for the vehicle weight, but seriously crammed into the compartment. Removing the intake manis/fuel rail/etc. to get to t-stat and problematic oil cooler cover (sealed at factory with sealant not even a gasket) is painful. Removing wheel, well shield, engine mount and blocking engine to get to water pump also not a joy. Outside stuff's supposed to be on the outside. Bulletproof stuff can be on the inside.

Thanks anyway, appreciate the shout.
Old 07-18-2015, 12:37 AM
derf's Avatar
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Hang around..someone may come along with the answer
Old 07-18-2015, 05:29 AM
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Thanks, I'm hoping so. This is going to be a pain if I have to dig any deeper into this engine.
Old 10-25-2015, 01:57 PM
Join Date: Oct 2015
Posts: 2
Unhappy My Saturn L300 Also leaking coolant

I haven't checked out anything yet, I just swapped the tranny on my L300 v6. Leaking coolant now. Resevoir pot is empty and low light comes on. When I dig in to it I'll update.
Also if you know anything about the transmission(automatic transaxle), it seams to be slipping like if you have a manual and rev the motor to high without fully releasing the clutch. It starts to smell and most of the time it will drop down into gear but its very inconsistent. Sometimes rough, sometimes it slides and if I'm on a slight hill it won't catch at all, simply just burn up something like the clutch. I stopped driving it to prevent any damage.
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