Need more heat

[Schurkey]

Same. Mines a 95, and hoses go from water pump, to heater core, to top rear of intake manifold, with no valve in-between.

More accurately, from right rear of intake manifold (the manifold is the supply of hot coolant) to heater core inlet, to heater core outlet, to water pump suction port.

The hot coolant comes OUT of the back of the intake manifold, and re-enters the engine at the water pump.

Some vehicles have the outlet of the heater core plumbed directly into the "cool" tank of the radiator. The cool tank of the radiator is connected to the suction side of the water pump via the lower radiator hose.

 

[PlayingWithTBI]

Some vehicles have the outlet of the heater core plumbed directly into the "cool" tank of the radiator. The cool tank of the radiator is connected to the suction side of the water pump via the lower radiator hose.

Yeah, I think the TBIs go to the radiator (at least mine does) and Vortecs go to the water pump? But not sure.

 

[Dover]

Yeah, I think the TBIs go to the radiator (at least mine does) and Vortecs go to the water pump? But not sure.

My 90 TBI returns from the heater core to the radiator.


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[shallow183]

Did you ever pressure test or use a block tester on the cooling system? The temperature fluctuation and no heat makes me think head gasket.

 

[n8pu]

Did you ever pressure test or use a block tester on the cooling system? The temperature fluctuation and no heat makes me think head gasket.

I'm sure he has already checked the coolant level in the radiator, but I have had that happen to me before. But as you suggested, I finally had the intake manifold gasket replaced, that was a few years ago and the fluid lever has stayed constant without the need to add more and have had good heat as well.

When they replaced that gasket they said that one of the cylinders (driver side front one I think they said, number 1 [one]) was showing signs of a little seepage too.

 

[nhyrum]

Did you ever pressure test or use a block tester on the cooling system? The temperature fluctuation and no heat makes me think head gasket.

I've heard head gaskets can cause bad heat. And I've just only replaced leaking freeze plugs, so I knew I had coolant loss there, but the last oil analysis I had done, they didn't find any coolant in the oil, so that makes me think a head gasket is less likely (I'm not ruling it out entirely). But I haven't had it pressure tested.

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[shallow183]

I've heard head gaskets can cause bad heat. And I've just only replaced leaking freeze plugs, so I knew I had coolant loss there, but the last oil analysis I had done, they didn't find any coolant in the oil, so that makes me think a head gasket is less likely (I'm not ruling it out entirely). But I haven't had it pressure tested.

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I was just thinking that might be where your possible air in the system is coming from. Especially since you have gone through it and replaced a lot of components. Do you have a funnel with the radiator cap adapters? Those help alot

 

[Ehall8702]

So I skimmed the thread and have sum Info that may help. We put two heater cores in my bosses Jeep liberty before we finally put a Mopar core in it. The two cheaper ones just didn't have any good heat no matter what we did ( we are both state certified mechanics and ASE mechanics and this is what we do for a living too). Once we got the Mopar core and compared it to the dorman core you can see why , the dorman was Waaaay inferior, had half the cooling tubes and less cooling fins. Did they put a cheap core in it? Could be the issue , worth checking out. Also, we end up letting muratic acid sit in the core ( unhook both hoses and hold em up and fill one side with acid till it starts to almost come out the other hose) for about 10 minutes and then flush with water, but that's for an old plugged up core and it works about 90% of the time.

 

[nhyrum]

So I skimmed the thread and have sum Info that may help. We put two heater cores in my bosses Jeep liberty before we finally put a Mopar core in it. The two cheaper ones just didn't have any good heat no matter what we did ( we are both state certified mechanics and ASE mechanics and this is what we do for a living too). Once we got the Mopar core and compared it to the dorman core you can see why , the dorman was Waaaay inferior, had half the cooling tubes and less cooling fins. Did they put a cheap core in it? Could be the issue , worth checking out. Also, we end up letting muratic acid sit in the core ( unhook both hoses and hold em up and fill one side with acid till it starts to almost come out the other hose) for about 10 minutes and then flush with water, but that's for an old plugged up core and it works about 90% of the time.

You know, I wondered if there could be a difference. I thought you could get more heat into the air by making the fins taller, with more surface area and more loops for the coolant. I have no idea what brand of core they put in, but seeing as they busted my heater box, id bet my first born it's not an oe one

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[Ehall8702]

You know, I wondered if there could be a difference. I thought you could get more heat into the air by making the fins taller, with more surface area and more loops for the coolant. I have no idea what brand of core they put in, but seeing as they busted my heater box, id bet my first born it's not an oe one

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That is the MO of most shops is to use aftermarket parts, it keeps cost down for the customer in most cases. We have learned over the years what parts you can and can't use aftermarket for , heater core was added to the list a year and a half ago lol. O2 sensors , and most engine and trans sensors were already on the list. At a few bucks difference and I don't have to replace it later on my own dime it's worth it to get oem the first time. Especially a job that's a straight PITA to do, why would you chance a sub-par part?