Changed water pump & thermostat. Still only blowing cool air. Fan motor blows fine Jeep is in good condition other than this. Someone mentioned using some different antifreeze?
if you were the person that changed the water pump and t'stat this will be more of a 'follow-on'
A word of warning and advice, if you are going to work on the cooling system when it is in operating range, ie hot! Wewar a long sleeved work shirt /coveralls, work gloves and eye protection. If a hose 'blow's" when you are in proximity to it, it will cause injury. if you are caught like that, wash the affected with cool water a.s.a.p. and for a minimum of 15 mins. One, the washing will remove any anti-freeze, (bad for the skin etc) Two, the cool water will reduce the temp and thus the damage to the outer and inner skin formation. Most important to cool the UNDERLYING skin, it will greatly reduce reaction and damage.
Ok, here we go. If you8 have an assistant it will save you some tiome. The engine is warmed up and is at operating temp. Briefly check the top rad hose between thermostat and rad. If it's hot to the touch, the T'stat has opened, if cool to the touch the T'stat has NOT opened. Re'check the T'stat installation.
All is well, rad top and bottom hose are hot, coolant is circulating. Find and follow the heater hose from engine to bulkhead. Sometimes there will be quite a few hoses sharing a common center. Again, check that the inlet hose to the bulkhead and the return line are hot to the touch. This equates to coolant circulating. if inlet is hot and outlet cool, then the coolant is not circulating correctly through the heater box / matrix.
Under the hood, find and trace the vacuum line (s) which run from the engine to the bulkhead and check for leaks, a broken connector or a split hose. The underhood temps cook vacuum lines fairly easily, making them brittle. No problems found? Obtain /rent a hand powered vacuum pump, disconnect the main vacuum feed to the bulkhead, (under hood), attach it to the hand powered vacuum pump and operate the pump. If you have an assistant, have them sit in the vehicle as you operate the pump, WITHOUT the engine running. They should be able to hear the flaps on the airbox open and close. if they cannot hear them operate, there may be a vacuum leak inside the dash from a damaged line T-piece etc. To double check, start the engine, and operate the vacuum hand pump. Ensuring that you have plugged the vacuum source on the engine otherwise you may have poor starting, and a lumpy erratic idle.
Have your assistant operate the heater controls whilst you operate the vacuum pump. If the air flaps operate with the vacuum which you supply, and the heater mode directs hot air to the interior of the vehicle, then you have narrowed the problem down to a faulty vacuum feed at the engine supply.
Anti=Freeze enables the boiling point of the coolant system to be raised, and of course, depending on the mix, prevents the coolant from freezing at low temps. Do not mix the Anti-Freeze more than 50% Glycol and 50% water. Odd thing about anti-freeze, if you increase the glycol content, the engine will start to operate at a higher temp, with the usual problems which come with that situation. Certain Anti-Freeze mixtures have additive's included which are kinder to cooling systems which have a high aluminium content. In any case, after two years continous useage, Anti-Freeze properties start to decline and the coolant system requires draining /re-filling with new Anti-Freeze.
Hope that info is of some help.
Jan 25, 2011 |
1998 Jeep Cherokee