How to test radiator & water pump?

Fearless1 · June 15, 2016, 12:58 PM

1987 Allegro 454 Engine pegs temp gauge. Replaced radiator cap & thermostat-OEM-195. Next would be radiator & water pump? How to test w/1 man show?

boogie_man · June 15, 2016, 04:40 PM

Check your actual gauge itself to make it's working. They're known for going out as well as the sending unit area....mine did.

Rickf1985 · June 15, 2016, 05:55 PM

If it is pegging the gauge and not boiling over then it is a good bet the problem is the sender or gauge. Check the wire on the sender and see if it is on the unit, if it is then unplug it and see what the gauge does. If it does not move then either the gauge is bad or the wire is shorted somewhere. If the gauge drops all the way down with it unplugged then I would replace the sender as the next step since all the other steps are going to be involved. Do the easy cheap ones first.

EldoradoBill · June 15, 2016, 08:21 PM

x2 on dash gage notoriously inaccurate. I've always felt the top hose and the bottom hose, if you can keep your hand on the bottom hose longer than the top then you're good.

Fearless1 · June 16, 2016, 06:54 PM

Forgot to add: have installed new temp sensor and gauge works, don't know if it's accurate. Yesterday, with radiator cap off, when needle touched RED, coolant was boiling. Just checked it cold, needle was about on 3/8 mark. Turned key on and off, needle goes to about 1/4 on off, and almost touching the "0" mark when on. i?? Thoughts? Suggestions?

legomybago · June 16, 2016, 07:38 PM

If your coolant was boiling when your gauge was in the red, your gauge is working great! Now for the bad news....

Rickf1985 · June 16, 2016, 07:55 PM

Sounds like a blown head gasket. Get yourself a combustion analyzer kit for the coolant. Combustion gas in the coolant is a blown head gasket. With the radiator cap off and a 190 thermostat it is pretty normal for water to come out as it heats up just from expansion. If you have a laser temp gun or know someone who has one point it at the thermostat housing once things get hot and see what the water temp is coming out of the engine. If the engine is not boiling over with the radiator cap on then I would not say head gasket just yet without a combustion gas check. Have you checked the area between the radiator and AC condensor to see if it is clean and not full of leaves and junk? And is the fan clutch engaged?

Fearless1 · June 17, 2016, 08:50 AM

Radiator area is free of debris. I did the spin test on fan, it stops immediately when released. Doesn't have any side to side play. Fan comes on when engine starts. How to check if fan clutch engages? Will check on analyzer kit and temp gun.

Rickf1985 · June 17, 2016, 10:24 AM

If fan clutch is engaged the fan will be roaring like a jet engine you WILL know it. If fan is disengaged it will still be turning but not at full speed. if you rev the engine the fan noise stays about the same then it is disengaged, if it is roaring and increases as you rev it up it is engaged. It normally will be engaged when you first start the engine cold and will drop out after 30 -60 seconds once the viscous oils in the clutch move around. Then it will not come in again until hot. It sounds to me like it is not engaging.

Fearless1 · June 17, 2016, 11:19 AM

Have not heard that loud noise from fan. Sounds like it could be the problem, or a part.
I'm thinking it's going to be lots of fun changing it?

Rickf1985 · June 17, 2016, 03:57 PM

PM Tiinytina, She has the same unit, or real close to it. They are all different when it comes to access to the front of the engine. It is only four bolts that hold it to the fan and four nuts holding it to the water pump. The biggest problem is getting it out of there. W% Make sure you get a thermostatic clutch and NOT a centrifugal clutch. And get the heavy duty one, that is a big fan.

Fearless1 · June 17, 2016, 04:48 PM

When pegged temp at thermostat housing is 212, at motor 236. It may could have gotten higher, but I cut it off. Did notice a difference in the noise level of the fan. Does that mean it's good? Didn't notice it until it quietened for a few seconds. My loss of bilateral hearing may be a factor.

Rickf1985 · June 17, 2016, 06:55 PM

You will also notice a substantial increase in airflow with the increase in noise. 212 at the thermostat housing on a 190 thermostat is not all that unheard of but a little high for just sitting still. Where on the motor did you get the 236? That would sound like the thermostat just opening at idle to me. The fan would normally kick in about 20 seconds after that as the hot air starts coming through the radiator and hitting the sensor on the fan clutch. I have very poor hearing in my left ear and not so great in the right but like most it is in the mid-range and the fan is in the lower range, you will hear it.

Fearless1 · June 17, 2016, 07:42 PM

Rechecked motor temp from underneath, on block beside inside spark plug, close to middle - 376. Is that too hot? Still haven't heard that loud noise. This time, after reving it a little to heat up, when needle started to move, I let it idle. Didn't notice any change in noise level after needle hit RED, then I got the reading underneath. i??

Rickf1985 · June 17, 2016, 08:59 PM

376 is way to high for anywhere except the exhaust manifold. What is the history of this thing? Was it running good and this started or did you buy it this way? A laser temp gun has limitations, there are certain areas you can shoot and read the results but other areas that you really have to know what it is pointed at to be able to interpret the readings. Kind of need to know what was going on leading up to this.

M & J · June 17, 2016, 09:54 PM

To me it would appear your radiator is nearly plugged or the water pump impeller has lost all the vanes. You said the hose and radiator gets hot but is it moving much water?
Rick also said a blown head gasket will cause over heating and you can buy test strips to check for combustion byproducts in the antifreeze. If you can see in the radiator is water flowing? Can you see a shiney or shimmering on the surface from petroleum products? We also have an 87 Allegro and seeing down in to the radiator is impossible without a mirror.

Rickf1985 · June 18, 2016, 09:51 AM

Quote from: M & J on June 17, 2016, 09:54 PM
To me it would appear your radiator is nearly plugged or the water pump impeller has lost all the vanes. You said the hose and radiator gets hot but is it moving much water?
Rick also said a blown head gasket will cause over heating and you can buy test strips to check for combustion byproducts in the antifreeze. If you can see in the radiator is water flowing? Can you see a shiney or shimmering on the surface from petroleum products? We also have an 87 Allegro and seeing down in to the radiator is impossible without a mirror.

Mike, Can you get to your fan clutch without removing the radiator?

Fearless, At this point we need a little history to try to diagnose this any further on the net. Kind of hard when we are not there looking at it in person.

M & J · June 18, 2016, 11:46 AM

Not from the top since ours still has the fan shroud. Not sure from underneath.

EldoradoBill · June 18, 2016, 12:01 PM

You can access the fan clutch through the inside engine cover and if necessary can change it out without removing anything else. It's not easy but doable, 4 bolts to the pump and 4 bolts hold the fan on, the fan needs to be separated first and left in the shroud area for the clutch to come out.

Bill

Fearless1 · June 18, 2016, 03:54 PM

Bought it last year and have not been able to take a trip yet. Major roof and water line leaks plus electrical issues, ground tied into hot, mucho fried wiring and junction blocks, alternator, lights, ignition switches and relays, fuel pump, etc. Lots of fun so far. :)rotflmao Temp gauge didn't work when purchased. Replaced sensor. Gauge works...accurately? 376 temp was on head beside inside spark plug. Just rechecked on other side of motor on head beside inside spark plug - 436. After motor was running a minute or so, noise level dropped and didn't increase when temp hit RED. Checking top hose, coolant circulates, temp drops to 90's. Used mirror to check coolant, couldn't see anything unusual. [/size]Will go to AZ and get loner tool to test for blown head gasket.

Fearless1 · June 18, 2016, 03:59 PM

Got cut off for size__Checked coolant in radiator with mirror, nothing unusual noticed. Will go to AZ and get loaner tool to check for blown head gasket.

M & J · June 18, 2016, 04:03 PM

Not sure about a tool. What we were talking about are test strips you dunk in the coolant. The strip indicates the presence of combustion by products in the coolant by changing color.

Rickf1985 · June 18, 2016, 04:26 PM

There is a tool that draws gas up from the radiator through a canister and changes color if hydrocarbons present. Same principle, fancier method. I am thinking right next to the plug it might get that hot but not likely. Sounds like a coolant flow problem. The most accurate places to check with the laser are the thermostat housing, the freeze plugs, the radiator by sweeping all across it and see where it is hot and cool. Should be hot at the top closest to the water inlet hose and coolest at the bottom by the water outlet hose. If no change top to bottom then the radiator has a problem. Checking right next to the plug is very close to the exhaust and you could be picking up radiated heat. Also unless it is a high end temp gun they tend to be inaccurate unless very close to the spot you are checking.

Fearless1 · June 18, 2016, 05:56 PM

At about 18" away, checked front freeze plug, only 157, stat housing - 225, radiator much hotter at top than bottom. Haven't gotten it yet, but that loaner tool from AZ is a $25 deposit - A freebie on return. I can afford that.

Rickf1985 · June 18, 2016, 06:08 PM

Has this thing actually boiled over? With the cap on?