Dorman Manifolds (1 Viewer)
- Thread starter eseel
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Is there a big price difference between dorman and oem?
Last year, I got the pair of Lexus oem integrated cats for a hair under $1000 including shipping/tax/gasket.
Last year, I got the pair of Lexus oem integrated cats for a hair under $1000 including shipping/tax/gasket.
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Given the difficulty and labor/expense of manifold replacement, I would not chance it on non-OEM manifolds. The OEM manifolds have a lot of cracking issues as-is that were never addressed - so even a new pair will also crack just like the originals. Dorman parts are OK but usually lower quality than OEM, so you may end up with cracks even sooner in the future. Also the OEM Lexus cats are high-quality and will have more precious metals and better environmental performance than aftermarket cats.
The best bet for this repair is to get a set of Doug Thorley short-tube headers and retain your existing OEM cats. The Dough Thorley headers will give you more power and are not subject to cracking like manifolds. Long-tube headers are easier to install and provide even more power but you lose the front cats, so they may be a no-go if you live in an area with emissions inspections.
The best bet for this repair is to get a set of Doug Thorley short-tube headers and retain your existing OEM cats. The Dough Thorley headers will give you more power and are not subject to cracking like manifolds. Long-tube headers are easier to install and provide even more power but you lose the front cats, so they may be a no-go if you live in an area with emissions inspections.
+1 DT headers, that is a permanent fix unlike using the same crap factory design
DT headers does not come with CAT
Depend on where you live it might not be an option.
Also in aftermarket there are a few different level of replacement cat. Federal rated are about 1/3 of precious metals compared to OEM. California rated are 1/2-2/3 of the precious metals compared to OEM. None of the last as long as OEM but the chance you keeping the GX another 18 years and same mileage are very slim too. I heard the federal aftermarket only lasting 1 year. Only good if you want to sell right away.
Depend on where you live it might not be an option.
Also in aftermarket there are a few different level of replacement cat. Federal rated are about 1/3 of precious metals compared to OEM. California rated are 1/2-2/3 of the precious metals compared to OEM. None of the last as long as OEM but the chance you keeping the GX another 18 years and same mileage are very slim too. I heard the federal aftermarket only lasting 1 year. Only good if you want to sell right away.
The DT short tube headers allow the OEM cats to be re-used. The OEM manifolds are cut off just ahead of the cats, the DT headers are then welded in place of the OEM manifolds. These should be legal in most states as the high-quality Lexus OEM cats are retained and function as intended.
@Rednexus Can you elaborate on Long-tube headers are easier to install? I have the dreaded "tick" & would like to do DTs, but I from what I've read I thought both short & long tube would be equally terrible to install. Are the long tube easier just because you don't have to weld the cats back on (like with the short tubes)?
Thanks!
Yes that is the difference. Bolt on vs. difficult fab work in a tight space. Either way you are unbolting the motor mounts.
GX DAVE
SILVER Star
I recently replaced my driver side manifold with OEM last week. After doing the research the savings wasn't notable enough to justify a non OEM unit in my opinion, due to the fragile nature of the design I know the OEM unit would have the highest build quality of the factory style design, factory shortcomings included.
Also looked into DT short tube headers as this was of interest to me too but they are on back order with no posted lead time. I would have gone this direction but if you are not willing or able to wait weeks, potentially months or a year+ (eeeek!!!) then the DT headers are not actually a realistic option. I also live in NY and we need to pass emissions inspection here, so long tubes are not an option for me at this time as the truck is also my daily driver and need to pass yearly inspection to be road worthy.
Further more, you'll need to find a good shop willing to do the work on the DT headers to cut and swap the OEM cat, which depending on where you live will prove to be hard in and of itself, not to mention will not be cheap. I'd estimate an additional $500 + standard install rate. Explaining this job to your run of the mill mechanic as I tried to do turned out to be much more complicated than everyone on here likes to make it sound. Is it doable? Sure its doable, but realistically if you aren't having the work done on the DT headers from a reputable off road shop familiar with the task at hand, which as we all know will likely have a high hourly rate price point, then its really not worth doing at all in my opinion.
It is safe to assume you inquired about the doorman unit because you are looking to save some money, as we all are! Well truth is, realistically it is the cheapest option! So if you want the cheapest option go doorman, the OEM option will not be cheapest but will be more cost effective with a much quicker turn around than the DT option.
I really wanted the DT headers, it was just not realistic at for me at this time, take this for what its worth! Wishing you the best with your manifold endeavors!
Also looked into DT short tube headers as this was of interest to me too but they are on back order with no posted lead time. I would have gone this direction but if you are not willing or able to wait weeks, potentially months or a year+ (eeeek!!!) then the DT headers are not actually a realistic option. I also live in NY and we need to pass emissions inspection here, so long tubes are not an option for me at this time as the truck is also my daily driver and need to pass yearly inspection to be road worthy.
Further more, you'll need to find a good shop willing to do the work on the DT headers to cut and swap the OEM cat, which depending on where you live will prove to be hard in and of itself, not to mention will not be cheap. I'd estimate an additional $500 + standard install rate. Explaining this job to your run of the mill mechanic as I tried to do turned out to be much more complicated than everyone on here likes to make it sound. Is it doable? Sure its doable, but realistically if you aren't having the work done on the DT headers from a reputable off road shop familiar with the task at hand, which as we all know will likely have a high hourly rate price point, then its really not worth doing at all in my opinion.
It is safe to assume you inquired about the doorman unit because you are looking to save some money, as we all are! Well truth is, realistically it is the cheapest option! So if you want the cheapest option go doorman, the OEM option will not be cheapest but will be more cost effective with a much quicker turn around than the DT option.
I really wanted the DT headers, it was just not realistic at for me at this time, take this for what its worth! Wishing you the best with your manifold endeavors!
DT wait times are usually 2-3 weeks tops, have bought them twice in the last year.
GX DAVE
SILVER Star
Usually is subjective term and that wait time is still a crap shoot in my opinion, theres nothing on the website that guarantees 2-3 week turn around for delivery, had there been I may have reconsidered this purchase.
I was not in a position to roll the dice on the lead time. I needed to fix the manifold and also have my Y pipe repaired so I could mount my skids in prep for the upcoming CMCC event this week. For me it did not make sense to wait, though it might make sense for @eseel as they might have more time on their side and be willing/able to wait for the parts.
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My 2003 GX470 (closing on 20 years) did not have cracked exhaust manifolds. I was still running the stock oem ones when I replaced them due to continuous bad integrated cat P0420 and P0430 codes for like a year.
So, I don’t buy this notion that these stock oem integrated exhaust manifolds are crap. Are there reports of cracking? Sure. Is it an epidemic? No.
I went with stock Lexus exhaust manifolds $500 each with shipping, tax, and gaskets from an online Lexus parts dealer.
I was lucky and my trusted local mechanic only charged me $200 total in labor to install both.
The list of suspect parts on the gx470 based on speculation is long and makes me think it’s not a landcruiser….lol
1. Integrated cats exhaust manifolds crack sometimes
2. Rear 8” explodes at any time
3. Front sway bar end links break and damage the CV axles
4. Tie rods bend easily
5. Rear air springs will leave you stranded
6. Driveshaft thump on early models
7. Secondary air injection issues in VVTi models
8. Seized brake calipers
9. Paint peeling issues
What else? Knock on wood I’ve only experienced two of these issues, but this forum makes it sound like all these items are required preventive maintenance.
But I digress. If your exhaust manifold is cracking, you need to figure out if there’s a root cause of the cracking.
Has anyone cracked a DT?
So, I don’t buy this notion that these stock oem integrated exhaust manifolds are crap. Are there reports of cracking? Sure. Is it an epidemic? No.
I went with stock Lexus exhaust manifolds $500 each with shipping, tax, and gaskets from an online Lexus parts dealer.
I was lucky and my trusted local mechanic only charged me $200 total in labor to install both.
The list of suspect parts on the gx470 based on speculation is long and makes me think it’s not a landcruiser….lol
1. Integrated cats exhaust manifolds crack sometimes
2. Rear 8” explodes at any time
3. Front sway bar end links break and damage the CV axles
4. Tie rods bend easily
5. Rear air springs will leave you stranded
6. Driveshaft thump on early models
7. Secondary air injection issues in VVTi models
8. Seized brake calipers
9. Paint peeling issues
What else? Knock on wood I’ve only experienced two of these issues, but this forum makes it sound like all these items are required preventive maintenance.
But I digress. If your exhaust manifold is cracking, you need to figure out if there’s a root cause of the cracking.
Has anyone cracked a DT?
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I’ve owned 4 GX470s ranging from 80k to 290k original miles, all of them had leaking exhaust manifolds. It’s not loud, it’s a very subtle ticking noise, sometimes it goes away after a short warmup.
I would wager most people don’t even notice it on their own trucks.
Makes your GX sound like an old crappy american v8.
Without the leak a stock GX is quiet as a mouse, you can barely hear the engine running.
I would wager most people don’t even notice it on their own trucks.
Makes your GX sound like an old crappy american v8.
Without the leak a stock GX is quiet as a mouse, you can barely hear the engine running.
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My GX470 is very quiet.
The list of issues is what is commonly reported…not what I’ve experienced myself.
everyone's experience is unique.
And remember, you're unique just like everyone else.
I had cracked pass manifold. Replaced with stock from Toyota dealer, 14 months later THAT manifold cracked. I welded that up and ordered DT shorties in Dec 2021 (KNOWING there was NO lead time. DT makes them in batches and they had no known time for the next batch. I ordered from Rogue off road and was in touch with both Rogue AND DT during all this. Communication was good and they appreciated that I understood noone knew when the next batch would be made or shipped).
My weld sealed and quieted for 5 months then recracked. I glopped moar weld on that for a couple months.
My DT shorties took about 6 months from order to delivery but now I have them, and 2 weeks ago my driver side manifold cracked. So yeah, old 'merikun V8 sound coming from under my Lexus. It bugs me but hopefully in the next month or two i can align and schedule with a buddy to put the GX out of commission for a time and get this job done..
I also ordered stock gaskets, engine mount insolators and a transmission mount. I should at least get new driver studs and nuts as the passenger side set is only 2 years old now.
Trials and tribulations of a quality BUT 14 yr old vehicle with north of 230k miles.
And remember, you're unique just like everyone else.
I had cracked pass manifold. Replaced with stock from Toyota dealer, 14 months later THAT manifold cracked. I welded that up and ordered DT shorties in Dec 2021 (KNOWING there was NO lead time. DT makes them in batches and they had no known time for the next batch. I ordered from Rogue off road and was in touch with both Rogue AND DT during all this. Communication was good and they appreciated that I understood noone knew when the next batch would be made or shipped).
My weld sealed and quieted for 5 months then recracked. I glopped moar weld on that for a couple months.
My DT shorties took about 6 months from order to delivery but now I have them, and 2 weeks ago my driver side manifold cracked. So yeah, old 'merikun V8 sound coming from under my Lexus. It bugs me but hopefully in the next month or two i can align and schedule with a buddy to put the GX out of commission for a time and get this job done..
I also ordered stock gaskets, engine mount insolators and a transmission mount. I should at least get new driver studs and nuts as the passenger side set is only 2 years old now.
Trials and tribulations of a quality BUT 14 yr old vehicle with north of 230k miles.
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Sorry I totally missed your post! I think we were on vacation, and I just now noticed this due to DRANGED replying
.The long tubes are easier to install because (1) no welding of the cats is required (they are a 100% bolt in) and (2) the tubes are lower relative to the exhaust ports, compared to the ST headers. The tubes for the ST's are really crammed in order to fit them in between the engine and cats, whereas the LT headers allow the tubes to be positioned a bit better since more room is freed up with the cats going. It's still super-cramped, but looks to be better than the ST's.
The LT's are still terrible to install - see my build thread where it took me 3 days as a DIY (albeit due to some rusty manifold nuts/studs). With ST's, my GX would have been down for at least a week as I would have had to pull the OEM manifolds and send them out to get the OEM cats TIG welded to the ST headers. Also, I was able to get around $600 in scrap value for my old cats, which paid for most of the LT headers.
A competent shop can do the shorties in 6 hours but will charge more than that. I paid $900ish for install with new cats. Well spent vs. sacrificing a full weekend or more.
@Rednexus and @jiggletits:
thx guys....
- Is it possible to weld OEM cats to the DT LT's?
- Does anyone know how much performance gain should be expected with the DT ST's?
thx guys....
The LTs retain the OEM secondary cats in the midpipe, and only omit the primary cats. So the GX would not be catless. But it is not possible to add cats to the LT headers themselves - they are comprised of multiple tubes that come together just before the collector and start of the midpipe.
If you want/need to keep all 4 cats, I'd go with the STs.
LT terminate in a flange which bolts up to stock flange upstream of 2nd cat. To retain 1st cats to LT headers (or welding a flange to cat and bolting up to LT) you'll end up doing custom downstream of header replacing the Y-pipe to get 2 cats on each side before the Y-junction going into the single exhaust. At that point, might as well go full custom with twin pipes, each side has its 2 cats, resonator and muffler, or aftermarket with appropriate cats and muffler(s).
The LT bolt up to the stock downstream flanges overriding the 1st cats.
LT are 4:2, 2:1 collectors
The ST get stock 1st cats welded to them, but this is a fiddly process.
Unbolt engine from mounts and jack up, remove manifold and cut top of cats off per DT instructions, loosely fit header to block and lower onto mounts, mock cat to header and align downstream flange (repeat previous as needed to get proper alignment of cat to header in situ), tack cat to header, remove header and cat, fully weld cat to header, replace header with cat to block and bolt up, lower engine and bolt up mounts, bolt it all together.
ST are 4:1 collectors.
Pics from DT instructions (linked above) showing location of cut to be made removing cat from manifold tube and cat welded to ST's open pipe
The flange downstream of the 1st cats downstream of the manifold bolt up to the flanges in pic above right.
Each side is: block, manifold, bend, cat, flange;
driver goes pipe/bend, cat, bend, tube, bend, flange to Y-pipe collector;
passenger goes pipe/bend, cat, tube with Y-collector from driver, then flange;
then pipe, muffler, bend, flange, pipe, bends, resonator, pipe, tip.
Sadly, I haven't been able to find a singular diagram showing all this as is laid out in the truck...
Not meaning to hijack this into a DT header convo. I just wanted to share my stock manifold experience, but we know how snowballing repairs-come-mods work.
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