fever

[Fast Fords]

well, my truck broke out in to a fever on the way home from work today. here is the info:

1995 Ranger reg. cab 2wd 5 spd no a/c
2.3L with 148,000 kilometers. i have just replaced the heater core recently and properly (to my knowledge) purged the system of air. The rad cap, thermostat and gasket, along with the temp sender on the housing t are new, as well as a swapped in mazda b-series instrument cluster.
The thing is, i was driving up a hill in third running about 3,000 rpm and the temp gauge just skyrocketed. as soon as this happened, my check gauge light came on and the needle was almost out of the lined area for the temperature gauge (almost touching the "H"). Then, when i shifted into 4th gear, the needle dropped like a stone to the middle range, then creeped back up to sit halfway-3/4 the way to the "H" all the way home. My speed was 85-90 km/h and engine was turning at 1,750-2,150 (approx ), and i didn't pass anyone on the way home. What gives? it worked fine before the heater core/instrument cluster swap. the coolant is the proper colour and mix and topped up as well. any suggestions?

 

[ati190]

I would verify tempature with a mechanical guage first. When you swapped the cluster from a mazda b series, did you get a cluster from a 2.3?, or a 3.0, or 4.0 6cyl? If you got one from a 6cyl, your guages might give a false reading. Also, installing a mechanical guage will give you a more detailed reading of the actual temp, not just C or H. I would also check to see if your fan is operating correctly. Did you see any symptoms of it overheating, boil over etc?

ati190

 

[Fast Fords]

checked the coolant, no signs of boiling over, leakage etc. everything was top notch and good to go for the coolant aspect. and the thing about the v6 is i had a 1999 4.0L gauge outta a ranger put in an that gauge worked normally..i guess i will have to try hooking my beast up to a mechanical sensor, or take a run in it and let er warm up then check it with a thermometer and see what it reads...whats the rangers supposed to run at? i can't recall at all what it was supposed to be..thanks muchly for the suggestions, gives me somewhere to start..i will give the fan a good check over tomorrow. it seemed fine, but you never know



oh and the top rad hose was fine temperature wise; not too hot but definately hot enough to open the thermostat..there was plenty of heat in the cab etc etc..

 

[ati190]

sounds normal, but check the tempature with a mechanical guage of some sort (thermometer will work), but more importantly install a mechanical guage in the cab. Monitor the tempature accurately at any given time! Stock thermostats are 195's if i remember correctly. If you do indeed find it's overheating, I would change out the thermostat again as a starter, also make sure the radiator cap isn't defective, and installed properly as this can cause these sort of problems.

 

[Fast Fords]

it did it again today; i'm going to get one of those thermometer thingys to check it out at work..i think that is a great idea. i will check out the rad cap as it is the easiest thing to check and then do the thermostat as that is relatively alright as well..thanks for the ideas; points me in some sort of direction

 

[fordboi415]

i would replace the thermostat with one that fails in the open position to avoid it going bad and overheating your engine even if it is new ive had them fail after just a few weeks, and drill a small 1/16th" hole in the flat part to help purge air

 

[Fast Fords]

i replaced the thermostat today, purged the system of air as well, and took it for a drive. Warmed right up and stayed right at half..got home, popped my rad cap, topped up the coolant and put some in the reservior as well. Changed my oil (all good; important to note, no signs of any foreign substance at ALL), and took it for a drive 2 hours later..started getting hot again. checked my upper rad hose, was pretty hard in pressure. checked my lower rad hose, and it was cool. Heat in the cab was plentyful, but the temp gauge just kept skyrocketing..so here is what i did. I released the pressure in the system by turning the rad cap back by one turn, and drove it. No spillage of coolant and no over-heating!! WTF?!?! i am extremely confused by this..is this a sign my rad cap is fawked or that my truck is building too much pressure; possibly caused by trapped air in the cooling system? or is there anything else?

the top rad hose and both heater core hoses are quite hot and full of pressure..dunno what the issue could be..

 

[RangerFabWorks]

sounds like you need to flush your rad out. you probably got crap in there. when you turn the cap your releaving the pressure in the rad therefore it wont overheat. how much psi is you cap rated.

 

[Fast Fords]

sounds like you need to flush your rad out. you probably got crap in there. when you turn the cap your releaving the pressure in the rad therefore it wont overheat. how much psi is you cap rated.

the rad cap is 16 PSI...how you think i should flush the rad? i dumped water through the top through where the top rad hose connects to the rad..and also through where the rad cap goes..only coolant then clear water came out, unless there is a better way to flush it..

 

[RangerFabWorks]

prestone has a radiator flush kit. look for it at auto zone, aid, napa, advance. really any auto parts store. i usually blow compressed air through the bottom. this will cflear out all of it. also. get a lower psi cap. try to get something around 7 psi. the higher the psi, the more likely youll blow a core out.

 

[Fast Fords]

hey i appreciate it! i'm gonna start with the 7 psi rad cap and see where it gets me; then if i need to i will flush the rad out..

thanks again man!

 

[RangerFabWorks]

glad to help out a fellow ranger friend.

 

[Fast Fords]

k this is my update..took for a 20 min drive and here is my findings...

rad cap on fully (pressurizing the system), drove 10 min from cold; reached operating temperature in 6min an blew warm air in 7min. Speed was a consistant 97-100 km/h and engine speed was 2,100-2,250 RPM, no passing/stopping. Coolant gauge in operating temp range. No fluctuation. Engine braked down a large hill in 3rd gear maintaining 50 km/h at 3,000 RPM for 45 sec-1min; coolant gauge good as well. Came to complete stop. Checked on upper rad hose; good. Drove up same hill that i just came down; 3rd, 50-65 km/h 3,000-4,000 RPM (approx.), heat gauge started to rise. Got to top of the hill, shifted to 5th..RPM 1,700 and speed 75 km/h, gauge dropped to normal range. Went down a side road and did some "acceleration" tests. Started from dead stop and floored it to 5,000 RPMs before shifting all the way up to 100 km/h. Gauge went up, but not too high. Did this once more and gauge went way up. Checked rad hose, EXTREMELY hard. Shut engine off, waited for engine to cool down and relieved pressure. Put cap back on and backed off to "purge air" position. Replicated exact test as written before; coolant held out at normal operating temp range, however; on uphill climb, slight increase was noted. Dropped like a rock as soon as i shifted to 5th. Maintained speed of 100 km/h home. Coolant gauge stayed the same.

I will be replacing the rad cap tomorrow for a 7 psi one and re-testing.

 

[Fast Fords]

put new rad cap on (13 lbs was all the parts place had) and re-tested..seemed to like the cap but still got hot after driving it for a bit (not nearly as much with a]the old cap and b]before the thermostat change). Flushed the rad 2x, put in brand new coolant, no difference. Still a buttload of pressure but the rad came out clean. the new cap is good and i have NO leaks. i think my rad is hopelessly clogged.....any ideas? i've been scratching my head soo hard at this one i might become a bald 19 yr old!

 

[LEVE]

I'm wondering if the Cat Converter isn't plugged/plugging. When you go up that hill the debris clog the exhaust outlet. That traps heat in the engine, and it raises back pressure, that causes power loss as well as an overheat condition.

Do the test again, at night. When the problem occurs, stop and lift the hood. Look at the exhaust manifolds and the Cat Converter. If it's really plugged the heat will cause these parts to glow a dull to a cherry red. It is quite impressive...

Also, go to a Mom and Pop muffler shop and have your back pressure tested. Usually it is a free test. Banging on the Cat Converter with you hand will also tell you something. Often, if it's bad, you'll hear the debris rattling around.