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98 Regal still overheating

Linika

New member
6
1
3
Buick Ownership
98 buick regal
I am working on my Grandmas car..
my family bought a crazy cheap car for her grrr...

So I have already changed the
water pump
Coolant temp sensor
thermostat
belt
re-wired the coolant temp sensor connections because they were fried

before all the work it was overheating fast, mostly when at stop lights and idling.
if the vent is on and driving fast the temp came down but not a lot.

now after all the work it lasts longer.
I took it to test while driving today and it was doing really well. then the Temp rose fast and when I turned it off coolant flooded out of the reservoir

radiator fans do turn on
there is also some brown sludge under the radiator cap
I also had added blue devil head gasket sealer when refilling the coolant after changing the water pump..

also note tomorrow I take it into dealer for a recall service for the valve cover leaking oil onto the manifold. Not sure if that is connected

I have no idea what to look at next :(
 

97PA

Member
39
20
8
Buick Ownership
1997 Park Avenue
I would look at your problem being a flow issue with the radiator, given the age (assuming its the original radiator), the typical DexCool sludge and the added Blue Devil treatment. I just posted a few days ago to another member with a 2004 Regal with overheating problems and it looked like after he checked over the things I suggested we both concluded the radiator was most likely the problem. I haven't heard back from him if the radiator replacement solved his problem. Before replacing the radiator, run the car to temperature and feel the bottom hose. If the radiator is plugged, the lower return hose will be noticeable colder than the top hose which connects to the thermostat housing. I use a cheap Harbor Freight non contact IR temperature gun (Ames) and take readings at several points on the radiator and at the hoses to better diagnose a plugged radiator but the suggestion I gave you about checking the lower and upper hoses will give you a good idea. I would also replace the radiator cap or get it checked, as this could cause overheating. Also make sure the cooling system doesn't have any air by following the air bleeding procedure (I loosen the 7mm bolt on top of the thermostat housing and run the engine until the air is released and coolant starts to flow). It can take a couple of bleeding cycles to completely remove the air, especially if you've replaced the water pump.
 

G-308713

thank you.. Yes I have done 2 bleeds.. yesterdays was better

the radiator is not original. at least that is what I was told.
The lower hose gets hot but I had wondered about a clog somewhere but not sure.

was thinking of doing a flush.. I did not do that after water pump change.

Car is at dealer now getting the recall service done for leaky valve cover
 

Linika

New member
6
1
3
Buick Ownership
98 buick regal
@97PA

Thank you
I have bled the system 2 times..

I was told the radiator is not original
I just picked it up from the dealer where they changed the front valve cover and gasket for free as part of a recall.
its super hot here today and it did overheat on the way home only 4 miles. it was 98 degrees out.
when I got home and turned car off it was 2 white dashes from red and coolant over flowed the reservoir
also both upper and lower Radiator hoses super hot

the fans come on but I was reading another thread where someone talked about a higher speed.. How can I tell if maybe the fans are not turning on at the right speed ?
also I was running it with the heater on.. should I have been doing this with AC and not heat ?

I was thinking of doing a flush with something to clean it all out.
I did not do a flush after water pump change.. I think I should have but I didnt

also curious how to tell if radiator is blocked somewhere
______________________________
 
Last edited:

97PA

Member
39
20
8
Buick Ownership
1997 Park Avenue
You should have a high speed fan speed when commanded by the PCM when it detects a high temperature via the coolant sensor's ohm reading. I would run it with the AC on and no heater and see if the fan speeds change and whether it overheats when idling. On some Buick models it's the left side fan which goes to high speed during overheat and the right stays at the standard speed. One other way to test the fans is to unplug the coolant temperature sensor connection in put in a 130 ohm resistor in the plug harness. This will simulate an overheat condition to the PCM and command the fan(s) to high speed. You could still have a restricted radiator and cap, so after doing the fan check you need to consider these items. Another way to test a radiator is to empty out the coolant and disconnect both top and bottom hoses and then put a garden hose into the top radiator port and look at the flow rate at the bottom port. It should flow pretty freely and without restriction.
 

Linika

New member
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1
3
Buick Ownership
98 buick regal
Ok so I did a flush including a flush of a heater core which spit out weird stones that disintegrate when touched.
I used the prestone 2n1 cleaner

after the first flush the car started to sound funny and engine does a slight rev and has a gas smell from the exhaust pipe.
this did not happen before this

the temp guage never got past halfway yet did still overflow the reservoir but only on the first flush, it did not do that on the 2nd.

the fans turn on when I turn the A/C or heater on but I see no speed change and if I turn either off and let the engine just go the fans do not turn on and the radiator is hot.

both upper and lower rad hoses both get hot.
Now I did not bleed the system for air once I refilled with water to flush out for the 2nd time.
going to try and upload vids but here is a picture of the water from 1st and 2nd flush.. they look the a little different
I also got a few stones on the 2nd flush out of heater core.

oh new radiator cap

I spilled a bit on the driveway when emptying after the 1st flush and I noticed the rainbow film..does this mean gas in the coolant :(

also question.. if I put the hose on the pipe the heater core hose comes from the engine and flush... is that the flushing the engine ?

left bottle is first. it was darker before I thought of collecting in a bottle.
20190916_105622.jpg
 
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Linika

New member
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Buick Ownership
98 buick regal
here is video.. this is after I emptied the cleaner and water and refilled with water.
at the 10 sec mark you can hear it start to do that weird rev

 

97PA

Member
39
20
8
Buick Ownership
1997 Park Avenue
Those little brown balls are the ceramic material from the Blue Devil, rust and possibly an interaction with the DexCool. This is not good for the radiator passages, which could be blocked and will be difficult to clean out with just flushing. The fan operation sounds normal, as both sides will stay at low speed but the left goes to high speed only when an overheat condition is determined from the coolant sensor and commanded via the PCM to the fan. So, based upon your last update it sounds like the overheat issue has almost stabilized but I still question the condition of your radiator's passages. The smell of gas and the rev increase and noise are probably another issue. For sure, if it's too rich you're going to set a P0172 DTC rich code in short order as the long term fuel trims will go full negative to pull out fuel to the 25% max limit. Your method of flushing will probably work but I don't use it, as I crack the radiator drain plug on the lower left to allow draining and then I keep a constant flow of water with the hose through the radiator cap opening with the engine running at operating temperature. This is the fastest way to flush out the system. I keep the flow going until the color is clear and then turn off the engine, let it cool and then fill with Prestone All Makes green (never DexCool) with 50% distilled water. The rainbow sheen in the coolant normally means oil contamination (possibly from a blown head gasket or cracked block) but it could also be from the Blue Devil product and/or residual DexCool sludge.

At this point, I would go back and check the flow of the radiator from the top to the bottom based upon my previous posting and then bleed the system. Run it again with clean water in the system and see how it runs. I really suspect if you're finding this debris currently, a lot of it is probably clogging the radiator and still causing problems. If the radiator's flow is still restricted after flushing there's no way to fix it short of replacement.

As a side note, I want to give readers experiences with Blue Devil. I had a friend who flipped cars for a living and when the car he was going to sell had obvious head gasket failure, as confirmed with a block test to confirm the presence of CO2 gas (the fluid turned from blue to yellow), instead of properly fixing the car he would pour in the Blue Devil product and follow the exact instructions. In the three cars he did it with they worked well for a couple of weeks to a month but all failed shortly thereafter. In one case, with his personal car (1991 BMW 318I) he found out none of the machine shops would resurface the aluminum head after exposure to the Blue Devil's ceramic product, as he was told it messed up their cutting tools because of structural changes to the aluminum. So I warn anyone to not use this product if they want to keep their car. I don't know of one long term (over a year) success story with this product.
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Linika

New member
6
1
3
Buick Ownership
98 buick regal
ok so I filled with coolant after last flush.. overheating is better. I have not truly tested it out as the engine is acting weird and didnt want to over do it..

I did drive it to the auto store for a code read.
codes came back as
p0336 Crankshaft Position Sensor
p0305 Cylinder 5 - Misfire

now the weird engine stuff just started after the flush..
I also need to drain some oil because my grandma liked to over fill.. like alot..

and I have to admit something really stupid. there is a small possibility that I put a 1/4 tank of diesel.... I am usually very good about this when switching between the car and truck but thinking back of the day I took the car to the dealer for the valve cover and gasket replacement I am not sure about which pump I went to on the way to dealer..

I did a block test just in case of head gasket issue.. the test stayed blue at the radiator.. for kicks I did one at the tail pipe and it turned pale yellow
 

Linika

New member
6
1
3
Buick Ownership
98 buick regal
oh I forgot , I had to do the block test 2 times at the radiator.
the first time I had lowered the coolant as instructed but about 1 min in the coolant level came up fast and I sucked some into the tester.. oops.

2nd time I watched better. same thing started to happen but then went down and stayed down long enough for 2 min test
 

97PA

Member
39
20
8
Buick Ownership
1997 Park Avenue
I like the two chamber block testers because of the problem you experienced with pulling coolant into the single chamber units and fouling the test fluid. Based upon your response, I think you can rule out a head gasket problem. However, I think you've got multiple issues with the car, as the misfire is probably unrelated to the overheating. It's possible the diesel fuel could've been the reason for the misfire problems but P0336 is usually related to poor connection at the PCM, ignition control module or CKP sensor; damaged harness; malfunctioning ignition coil. The P0305 misfire is specific and could be spark plug, spark plug wire, coil, ignition module, compression, fuel injector or air leak. It takes a lot of diagnostic skills to narrow it down. I would suspect given both codes have the coil problem in common to check there first. I monitor misfires via my B&B Electronics scan tool for the live data and look at each cylinder misfire history and current data, which allows me to narrow down the problem.

Your problems are starting to get outside of the capabilities of a DIYer unless they have tools to properly diagnose them. It sounds like you've solved your overheating problems (I would still replace the radiator if it were my car). If the misfire problems persist after clearing the codes, I would suggest you go to a qualified shop for repair.
 
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