Slow coolant leak

[TucsonMike]

Is there an acceptable amount of coolant loss a vehicle will have over time? I have never really monitored coolant loss until the last few years when I had a lower intake manifold leak. I got that leak repaired about 3k miles ago ( I think) but I notice I have lost about 1/2 cup of coolant over 2600 miles. Car runs fine temps are fine and no visible external leaks or smoke during start up. I will continue to monitor to get a baseline before I decide if I want to do anything.

I've owned my 4runner since 2003 and currently has 280k

I have a v6 with 5speed and radiator is somewhat new.

Seeking out any advice

Thanks

MikeM

 

[Devbot]

It wouldn't hurt to do the gaskets as I suspect they're probably the culprit personally. When I did my intake manifold gaskets ALSO around 280k (as part of solving a different issue) I noticed the material around both coolant passages on both gaskets was heavily eaten away, as in if I had left it for another year I probably would've been leaking into one of my intake valves - they were all holding on by a hair. Given both the age and mileage our vehicles are approaching I wouldn't put it past things if you have the same issue. And considering you can buy the gaskets online fairly cheap and it's not exactly a complex job (just tedious, especially by yourself) I would give it a whirl and see if it changes anything. I went with felpro instead of Denso as they were much cheaper and have absolutely nothing bad to say
Worst case scenario it was a few bills and an afternoon down the drain but at least you can rule it out at that point

 

[TucsonMike]

Thanks for reply but I have already replaced the lower intake manifold gaskets. I should add the bypass and valley were dry. Water pump was dry and sparks plugs looked fine.

Thanks

MikeM

 

[Bad Luck]

Thanks for reply but I have already replaced the lower intake manifold gaskets. I should add the bypass and valley were dry. Water pump was dry and sparks plugs looked fine.

Thanks

MikeM

How are you determining that the coolant loss?

 

[spartacus]

Wouldnt hurt to test the cap for the correct psi. I believe its rated 15.6 psi. You can rent one from loan a tool program at the big block auto stores.

 

[3bears]

you say you did the lower intake gaskets 3000 miles ago and since have lost 1/2 cup of coolant.....was it all of a sudden ? did you just now noitice and have not really paid attention to it since the intake manifold gaskets ? Maybe it just needed to burp an air pocket.
I had a 2001 for a brief time, it would loose coolant...part of its issue is previous owner had installed wrong radiator cap

 

[TucsonMike]

I have been checking coolant level in the morning and right after I had gaskets replaced I was checking it daily. I'd say the first couple thousand miles I didn't see a drop in coolant and didn't check it for awhile and lately notice it was about 3/8 below the full line when engine is cold. I'll continue to monitor it and see if it drops any further over time.

I might pressure test it as well

Thanks

MikeM

 

[phattyduck]

I had a 2001 for a brief time, it would loose coolant...part of its issue is previous owner had installed wrong radiator cap

Been there, done that on multiple Toyotas. A new OEM cap fixed it.

Not saying that is the issue in this case, but also worth checking.

-Charlie

 

[TucsonMike]

I did by a spare cap and can try it to see. My current cap I replaced over 100k miles ago so I supposed it could be due. Doesn't hurt to try since I already have one

Thanks

MikeM

 

[JustTroItIn]

You can get some UV dye and glasses. If the leak is external this should help you locate it.