animus_divinus

recently, ive noticed the check engine light coming on.. temperature of the engine is a little high.. it has fresh, clean coolant, and an oil change a couple weeks ago... so im wondering what could be wrong

my guess is either a faulty pump for the cooling system, or its blocked somewhere... how would i test to see if the pump is working? or not, and if its not, does anyone have a guide to replacing it?... if its blocked, what are my options for unblocking it?

Blacklisteduser

Warm up the truck to operating temps, kill it and squeeze the rad hose, listen for a hissing if you hear one trace it down. If your pump is leaking or has a bad seal you will hear it.

At operating temps if there is a blockage, the heater 90% is the first thing to stop working, do you have heat?
Blockages don't usually, but they to sometime, happen in the pump side. Pull both of the little hoses that connect to heater core. Blow them out w a hose both ways. It will probally be wicked dirty.

This users opinions have been censored by the FCC

Blacklisteduser

Also I'm not sure if temperature affects the engine light...

May be a different issue.

This users opinions have been censored by the FCC

nukinfuts29

If the pump was bad you would be overheated a lot and loosing fluid. First thing to check is the fan and thermostat

Blacklisteduser

Stupid mechanical fans... forgot about that. Stupid clutch. :/ And if was a failed Tstat wouldn't the temp just continue to climb. I'm not a certified tech, but that exact issue happened to me. Turned out to be a water pump bearing would leak only when the coolant exchanged, leaving a bit of air in the head makin it run about 210-220. Never noticed the leak.

This users opinions have been censored by the FCC

animus_divinus

well, ill write these things down and check this weekend.. i believe the fan is still running, and ive never actually ran the heater as of yet.. so ill check these things out tomorrow

nukinfuts29

>>And if was a failed Tstat wouldn't the temp just continue to climb

Not necessarily. In fact a symptom of a bad thermostat is usually that the heat is blowing cold or not hot enough. The thermostat works like the switch on rail road tracks. When it opens it allows the collant to flow into another area of the system.

Blacklisteduser

Agreed, you would loose heater, if it fails open, right? You can't cool half of the coolant in the rad cause it's constantly flowing... So it would be a little hot not overheating...

What if it fails closed, that would cause overheating 'til something popped.

New Tstat on the list for sure (and the gasket) I suggest the failsafe one, it breaks "open" to prevent engine overheating. Rad caps are cheap I like to keep it same age as the Tstat.

This users opinions have been censored by the FCC

nukinfuts29

Here ya go

http://auto.howstuffworks.com/question248.htm

animus_divinus

so if the fan is spinning, then its not the pump and either a blockage, or a bad thermostat, and you guys believe its probably the thermostat? how would i test that, and test for a blockage?

nukinfuts29

I would test the thermostat. I only say that because you said the temp is a little high, but that and the CEL could be unrelated. Should pull the codes.

animus_divinus

well, turns out the heating system is just fine, everything works, and its running at 200 degrees... my cousin is able to read the OBD codes, and im going to post a printout of it in another topic, since it is something entirely different, and under a proper topic title will help anyone that may have a similar issue

Blacklisteduser

Only way I know to test a Tstat is to take it out and put in a pot of boiling water if it opens, good stuff. If not sod it.
But, you say it runs at only 200? Operating temps are just 195, maybe the warm weather is keeping you a little over normal. oshrugo
From what I read all over, jeeps have been battling this same issue forever.
Best way to win the fight is getting a electric fan conversion. Search the fabrication threads find a build u can do.

This users opinions have been censored by the FCC

rangermonroe

Describe "a little hot".

Both of my jeeps operate at 210.