As I was pulling in to have my 2003 V8 SR5 to be detailed, I was told there was coolant pouring out under my car. I opened the hood and the top radiator hose had come loose from the radiator. It was just sitting there with the clamp intact near the radiator tank. So, I opened the clamp and put it back on the radiator and drove home. It appeared to be fine, the hose wasn't split or deformed. Engine temp was normal throughout them entire process. So, I'm going to order a new hose and clamps but I am curious as to what might have caused this. My car is meticulously maintained. Any thoughts? Also, should I use OEM clamps or the screw type? Thanks in advance.

Jim Wells
Tallahassee, FL

How long has the thermostat been in?

Could be stuck.

Been in since new. That would cause the hose to pop off? Just asking.

Yes it could, IF it overheated, but you mentioned it never overheated.

That being said if the thermostat has never been changed it wouldn't be a bad idea to replace it, IMHO, think about it, it's 15 years old, think of it as preventative maintenance!

Has anyone ever check the hose clamps to make sure they haven't loosened over time, if not that could be the issue, once every year or 2 (10,000 to 15,000 miles) it a good idea to check all hose clamps, battery connections, nuts and bolts, etc., etc., all of this is required as preventative maintnenance from Toyota, not only under the hood but the entire vehicle.

Good idea on the thermostat. No, it did not overheat and the clamp appeared very tight. I had to use pliers to loosen it to get the hose back on. I'll add t thermostat and gasket to the order.

Jim Wells
Tallahassee, FL

I mean the clamps are spring clamps I wouldn't expect them to loosen up or lose too much tension over the years (actually I know they won't because I have had 80's Toyotas whose non rusted clamps are as springy as new ones).

When was the timing belt replaced on your vehicle? My guess is that the clamp was either not placed back onto the hose or not properly placed onto the hose and it eventually worked it's way off.

Within the last two months. I suppose that's very possible, because when I put the hose back on, it seemed very tight. I may take it back off and give it a close inspection? Do you use pliers on the clamp? Thanks!

If it's the stock spring clamp, I just use a pair of pliers to pinch it open and then slip it onto the hose. It helps if you try to match up where it was originally (you'll see indents in the rubber).

I have seen that type of issue a lot from body shops and other shops every now and then (and once from me long ago! oops!) . Radiator gets replaced or timing belt gets done and a hose clamp isn't properly reinstalled or forgotten, car drives fine for a day or a week until eventually the hose works itself loose and pops off.

I've never seen a spring clamp lose tension, unless it's corroded.

If it's been apart recently then it may not have been put back on correctly.

Thermostats are cheap insurance, and if they stick it can cost you an engine.

Easy DIY job? Loosen the 3 bolts and swap? Thanks!

Ok, I finally got to pull the hose and inspect the radiator neck and inside the hose are two pieces of plastic that appears to have cracked off of the radiator neck. They are somewhat angled so the hose could be pressed on.

So, do I need a new radiator or can this be fixed? If I need a new one, what brand? RockAuto has Denso for $127. OEM is $432. Think I'll pass on that.

Is this an easy job? Thanks!

I wouldn't be surprised if Denso is OEM.

I would replace it just for peace of mind of the hose not coming off again, Denso or Koyo are the best replacement brands to be looking at.

The job of doing the replacement is maybe a 3 or less on a 1-10 scale if you have the tools and more than just oil changing experience, IMHO a very easy job, but harder than changing oil, the 2 items you need to be very careful with are removing and reinstalling the transmission cooling lines, do not let the wrench slip on the fittings and make sure you have them treaded in straight before applying a wrench to them when reinstalling them, and be very careful not to do any damage to the cooling fins of the radiator, if you do bend them they can be straighten but it's time consuming.

Unless the hoses are new I would suggest replacing them at the same time

I can't tell from the FSM, but it appears it's a tension clamp on my 2003 V8 transmission lines? My mechanic told me he typically replaces the tension clamps with the screw tighten type clamps. Good advice? Replace coolant hoses, transmission lines or both? Thanks!

Coolant hoses, I would think any transmission hoses are OK, but I would at least inspect them for posible dry rotting/cracking, and yes I always replace the spring/tension type clamps with the screw type.