Mulestang

My daughter took my truck (2008 5.4 3v) to pull her horse/trailer tonight. On the way home, check engine light came on, followed by alert saying 'check engine temperature'. Dash gauge was pegged hot. Autometer temp gauge was reading about 220. She parked it and let it cool while I went to rescue her. I got there and temp had dropped to 150. Coolant level was ok. Started it up and headed home. Couple of miles from home, got the CEL and same check temp alert. Limped into driveway with water temp at 220, leak coming from somewhere under the radiator. I noticed that upper coolant hose was very hot and lower hose cool. Coolant level in reservoir was still in normal range.
Any ideas? Where do I begin?
Edit: Fan appears to be running normally.

nrivera04

redfishtd

I would replace thermostat , water pump and possibly radiator . If you don't have plate type transmission cooler add one . A flush for sure . Use distilled water for last flush .. make up your own 50/50 distilled water anti freeze , go a little heavy on anti freeze remember you can't get all the flush water out of this engine . Replace coolant reservoir cap ,it is your pressure cap . I don't trust this radiator depending on where leak is .
Cooling needs anti freeze too not just for freeze protection . Failure to use anti corrosion can ruin whole motor . It can turn to mud due to heating and cooling cycles .
My step sons did just that . They didn't have money for anti freeze ruined engine in two years they just used a hot bulb in winter . Your engine system is one big boiler . .

Mulestang

Thanks for your replies. I just replaced the thermostat and flushed coolant about 30k miles ago, so a bad t-stat sure would be a kick in the butt. Are there any ways to visibly check for a bad water pump?
The crappy part is that I'm leaving town for a month today, and my family can't go without the truck for that long. It's probably gonna wind up at the dealership. Ouch!

nrivera04

Bruski

Mulestang

Update: went out this morning. Truck starts and runs smoothly. Good oil pressure. However, I must have been wrong when I said the coolant reservoir was full. It was bone dry this morning. Took about 9 quarts of water to get back to full cold range. I'm guessing radiator leak?
Update: Yep...water leaking out where fan shroud meets lower radiator. I don't have any time to do it myself. Should I just let the dealership service department put in one of theirs or should I order one and have them install it? Are there better options than OEM? Up until now I've had no cooling issues. I'm thinking OEM is ok, but open to your opinions. Thanks

redfishtd

I would trust a good local mech to do this job . Radiators cheap on ebay as well as plate type trans cooler . , just make sure trans coolant lines are in the right spot . , with the money you can save not going to the dealer you can replace all and add trans cooler . Add trans drain pan and change all fluid out over a week 5 quarts at a time until you run thru 20 quarts of mercon V . Don't wait until trans acting up it will be too late . Change that pressure cap on reservoir.
Radiators are not fixable any more .

Mulestang

I'm already running a plug in my tranny pan, and the factory tow package cooler seems to be doing a good job. Would an additional plate cooler be worth the expense? Do you think it's a good idea to go ahead and replace the water pump, too? 130k miles on the stock one.

redfishtd

Not much complaint on water pumps . It is a lot of work to get to . If you have it all undone most guys will replace it . If you have factory tow that's great unless you do a lot in hot weather and around mountains . Some guys will replace all the pulleys and tensioner as a preventive. If you have electric fans its not hard to get to this stuff but the old style is a pain especially on the side of the road . .
Make sure you use wally world distilled water, its cheap . That boiling effect like your teapot will build up stuff fast . Your radiator is probably the main problem but change your pressure cap .
Good for you taking care of tranny .