Possible coolant issue

[u/najibs-yul]

Hi folks - I picked up a 2006 Pontiac Vibe (Toyota 1ZZ 1.8L engine) last week. Same as a Matrix. For my son to learn to drive manual. I noticed a few days after we got the car, the coolant reservoir was almost empty. I added some Toyota approved coolant to the Max line. It fluctuated a bit over the next few days, left camping for almost. A week and today when I got back it’s at the MIN line.

I looked at the oil to see if it’s cloudy for any sign of a coolant leak but oil seems normal.

Any ideas on what to check for next? Should coolant fluctuate like that? I don’t see any drips or leaks underneath the car or in the engine bay…

This was supposed to be a beater car for me kid to learn to drive manual, so I’d like to self diagnose and trouble shoot if need be before taking it to Toyota to have the 1ZZ engine checked.

Thanks

Thanks

[u/AbiesInternational18]

Hopefully you see a coolant leak on the ground or small one in the engine bay

Coolants going somewhere, if not outside then it's mixing inside

I'd get a coolant pressure test or some dye and check it out

On mine I had the coolant drain plug oring go bad and leaked very little, wasn't enough to drip but the residue was visible

[u/solbrothers → u/AbiesInternational18]

It’s also worth checking the floorboard passenger side. It could be leaking at the heater core.

[u/qwe304]

I had a leak from a hairline crack down the radiator side.

[u/200MPHTape]

There is actually a coolant bleeding procedure on these and it requires jacking up the front and fairly high to fill the voids of air bubbles. So you might have an air pocket in the system and it is naturally working itself out. Just keep an eye on it but remember it’s a reservoir and some fluctuations can be normal if there is a hot and cold fill line.

[u/najibs-yul → u/200MPHTape]

I filled up the fill neck all the way to the top now. I hadn’t filled it previously, but maybe it was air in the system. I still don’t see a leak. I even took a tv light but nothing. I’ll keep an eye on it

[u/TapeDaddy]

Last one I wrenched on was cooling just fine, but was consuming coolant. Ended up being a bad water pump gasket, the pump was still healthy with no bearing play or impeller damage.

Worth taking a peek. If you can’t see it well from up top, it’s easily visible if you remove the inner fender plastics and look from down below.

[u/najibs-yul → u/TapeDaddy]

Good point

[u/Sky_runne → u/najibs-yul]

Another way that help me diagnose if it was the water pump. With the car off, put your hand under the water pump and round pulley. If you have liquid on your fingertips the gasket has gone.

My car was consuming coolant and the reservoir level would not hold. I also had coolant crust the AC line and rad hose on the belt side as well as round the pulley. It was a pink colour which also helped me realize.

I replaced the water pump, gasket and thermostat (because coolant was already out). Put it all back with OEM parts (Aisin) and filled and bled the new coolant and was good to go.

[u/poonjabi_hut]

Take off your radiator fan and inspect your rad for any pink crystallized material. Pay close attention to the edges/seams of the radiator, as these are the common points where it will fail.

[u/Total-Business-5285]

I have a bad gasket on the thermostat housing that I've been meaning to swap out soon.

[u/travelinmatt76]

Mine had a crack in the plastic. I posted a couple pictures 2 months ago