2006 Tacoma 4.0L — losing coolant, refilling from low line every 300ish miles, no visible leak (302k miles)
Hey all,
I’ve got a 2006 Tacoma 4.0L with a little over 300k miles. The cooling system is all original (radiator, water pump, hoses, thermostat, etc)
Lately I’ve started noticing coolant loss but don’t know where.
- I don’t see any obvious external leaks
- No puddles under the truck
- No visible wet spots or crusty residue in the engine bay
It seems fine during short daily driving but on longer highway trips, I’ll come back low recently. Had to re-top off after ~300 miles.
At this mileage, I know the whole cooling system is basically end-of-life anyway, so I’m trying to decide how to approach it.
My question:
Would you guys start by pressure testing and only replacing what’s actually leaking, or just proactively refresh the whole cooling system radiator, water pump, thermostat, hoses, cap, etc given the age/mileage?
Also, if a pressure test doesn’t show anything obvious, what would you check next? Head gasket, radiator cap, water pump weep hole, etc.?
Just trying to figure out if this is a small fix or the start of a bigger “replace everything” situation due to age. I did take it into a shop recently to have the car looked at but they didn’t find anything with the radiator. They did give me a laundry list of approx 4500 dollars worth of over priced repairs (including $90 wiper blades) and told me I have a leaking oil pan that would be about another 2500 for labor but they don’t want to do it. I’m currently in the process of getting a new car but trying to keep this as a 3rd vehicle DIYing what I can and accepting things like that oil pan leak since I’m not adding oil between changes yet.
Thanks in advance!