Towed #3500 with my 5th gen

Recently acquired a cargo trailer setup for my business, and have been using it for a few weeks.
Yesterday I noticed the heater didn’t want to blow anything but cold air and the engine temp needle was moving between where it normally sits and higher up the gauge. Opened up the hood to find coolant sprayed all over. So I added some coolant today. Haven’t noticed any more coolant being sprayed or otherwise leaking but the heater and the engine temp gauge are still cornholed.
I had a thorough service preformed prior to towing on a regular basis…tranny, gear boxes, brakes.
How bad did I screw up my rig?

 

The trailer may have brought to surface an underlying issue with your cooling system. Go through the basics, belt/t-stat/coolant level & bleed...

 

Yeah I'd say bleed the cooling system properly. I doubt you did any harm.

 

How old is the 4runner? Did your thorough service include checking or servicing the cooling system as a specific task as part of the service? Where was spraying specifically?

Check the fluid level again. It will be burping out air for a bit, so you’ll need to keep an eye on it for a day or two and keep filling it. Not sure if you add coolant at the radiator cap or the bottle on the 4runner. But if you have the option of the cap, add it there.

hopefully this was just low coolant because it hadnt been checked in a while and not something like a leak fom tge rad or a hose

 

Spewing coolant in the engine compartment is very odd for a T4R. Although 3500 lbs is a considerable load for a 4R IMO, it's within it's abilities.

I've only experienced this with my (former) '03 Ford PSD 6.0 while towing a very heavy load. That engine's design flaw...well, one of them...was having a cooler with 2 sets of lines in it..1 for oil and 1 for coolant. The coolant would build up residue and not flow as designed, then flash boil from the hot oil jacket running next to it. It would send coolant up and out of the overflow reservoir and onto the underside of the hood.

My money is on a clogged radiator or bad thermostat and, as someone else said, the trailer has brought this weakness to the surface.

 

I doubt you hurt anything. I think Peter is right: you were on the threshold of a problem, and the extra load from the trailer pushed it over.

You might also look at the radiator cap. They can go bad and keep the cooling system from building pressure. Or it could be the thermostat stuck closed.

I'd start with the easy stuff... hoses, obvious leaks, and the radiator cap. You can get kits to pressure test the cap and cooling system. That might help pinpoint the problem.

 

Thanks for the input guys!
In response to the question above, it’s a 17.
I drove it abit this morning after adding some coolant. Checked it multiple time with no issues. Also jiggled some wires around at the front end of the engine.
I had no issue with the engine temp needle bouncing between normal and hot, also heater worked fine.
It’s going in to the dealer Thursday for alignment and rotation, going to have them take a look and see if they see anything.

 

Let us know how you fair out. I think a lot of guys tow that kind of weight with boats and campers etal.