Same Pentastar, same cracked plastic oil cooler housing — just under the hood of your Grand Cherokee, Durango or Ram instead of a Wrangler. We replace the housing and the failure-prone thermostat in one visit, at your home.
Every 3.6 Pentastar — whether it's in a Grand Cherokee, a Durango, or a Ram 1500 — carries the same plastic oil cooler and filter housing in the valley between the cylinder banks. Oil and coolant both run through it, the valley bakes it on every drive, and Ontario winters yank it through brutal temperature swings. The plastic fatigues, cracks, and the fluids cross over: coolant in the oil, oil in the coolant, or a slow external leak that pools invisibly in the valley before running down the back of the block.
On these non-Wrangler trucks there's a second, separate crack point: the manifold-side thermostat housing. When it goes, the thermostat can't regulate properly and the computer sets P0128 — coolant temperature below regulating temperature — which shows up as an engine that takes forever to warm up and weak heat in January. Different symptom set, same brittle plastic, same era of vehicle.
Because the intake manifold has to come off to reach the valley anyway, the only sensible repair is both parts in one pass. Contaminated oil is the real threat here — coolant strips the oil's protective film and bearings pay the price — so the housing replacement comes with a proper oil flush, not just a part swap.
If your Jeep / Dodge / Ram is doing any of these, this is the likely cause:
Two failure paths, two costs. The thermostat path is comfort and efficiency — long warm-ups, weak heat, a code that won't pass anything. The housing path is the expensive one: coolant thinning your oil with every kilometre until bearings start running metal-on-metal. If the oil cap shows mayo or the reservoir shows oil, the engine is telling you the fluids have crossed — that's a this-week repair, not a someday repair.
Yes — it's all accessible from the top of the engine. Intake off, valley housing replaced, thermostat done, fluids refilled and bled. About half a day in your driveway, on any of the three vehicles this engine lives in.
The part is buried under the intake manifold, so the bill is mostly labour to get there. Dealers also tend to treat the oil cooler housing and the thermostat as two tickets — same disassembly, billed twice. We do both in one pass and give you a single flat quote for the complete job before any work starts.
Coolant temperature below the thermostat's regulating temperature — in plain English, the thermostat is stuck open or leaking past, so the engine never fully warms up. You feel it as slow warm-ups and weak heat in winter. It's the manifold-side thermostat on these engines, and we replace it while the intake is already off for the housing.
Same engine, same valley, same plastic housing — yes. The non-Wrangler chassis adds the manifold-side thermostat as its own separate crack point, which is why our version of this job covers both. One visit closes out both known weak spots.
Send it over for a free second opinion. I'll tell you straight what the job actually involves — and if their quote is fair, I'll tell you that too.
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