My 98 4Runner has a small coolant leak. I took the skid pan off and the back corner of the pan was wet, the back corner that's under the starter. I can't tell where it's coming from. 3.4 v6 Any ideas?

 

Here are a few places to check:
Coolant lines going in and out of the throttle body.
Coolant line running along the back of the engine.
Water Pump (weep hole will expel coolant if it's going out).
Upper and lower radiator hoses.

Some of these are common sense and easy to check, others are more difficult. I just listed everything I could think of because coolant has an annoying way of running along something and then dripping down and fooling you as to the source.

 

It may not be coolant. Give it a sniff test. The discharge from the A/C condensation dumps in that area. Look for an aluminum pipe coming out of the firewall. Since I live in the high humidity of the gulf coast I've extended mine to prevent rusting out the drip pan.

 

taste it


you have a rear heater ? rear heater lines are the first thing to leak on
3rd gen cooling systems when they get 8-9-10 years old and have been
driven in snow and salt

 

Also, those hoses on the heater control valve like to leak..If they do..usually replacing with normal screw type clamp will fix the leak.

 

The heater hoses around the control valve were the first place I inspected. I didn't put the skid pan back on because I planned to change the oil today. It hasn't leaked since I removed the skid pan. I did have to add some coolant because the radiator and overflow were both a little low. I first thought it was a freeze plug or something. The head does seem (by touch) to have a freeze plug on the end facing the fire wall. I'm going to watch for this mysterious leak.

 

curious if you ever found the leak? My 99 has a leak that is very obvious with coolant stains running down the block, starter blocks the view. No visible signs of leakage up top, near hoses, etc? Usaully leaves a puddle on the floor after driving?